Existing law generally designates the State Air Resources Board as the state agency with the primary responsibility for the control of vehicular air pollution, and designates air pollution control districts and air quality management districts with the primary responsibility for the control of air pollution from all sources other than vehicular sources. Existing law requires the state board to inventory sources of air pollution within the air basins of the state, determine the kinds and quantity of air pollutants, and monitor air pollutants in cooperation with districts and other agencies.

Existing law requires the state board to adopt standards of ambient air quality for each air basin in consideration of the public health, safety, and welfare, including, but not limited to, health, illness, irritation to the senses, aesthetic value, interference with visibility, and effects on the economy. Existing law authorizes these standards to vary from one air basin to another.

This bill would require the state board, in consultation with specified entities, to develop, as provided, a response framework that establishes best practices and guidance for addressing fugitive and natural sources of hydrogen sulfide gas and for community preparation and response to hydrogen sulfide exposure events originating from these sources. The bill would require the state board, in developing the response framework, to conduct at least 3 public workshops, including at least one located in the Tijuana River Valley region, at least one located in the Salton Sea region, and at least one selected in consultation with a community that has experienced significant hydrogen sulfide exposure. The bill would require the Office of Environmental Health Hazard Assessment to update the acute and chronic reference exposure levels for hydrogen sulfide and to develop additional health guidance values for hydrogen sulfide, if the need is identified by the state board, in consultation with the office, during development of the response framework.

Existing law generally designates the State Air Resources Board as the state agency with the primary responsibility for the control of vehicular air pollution, and designates air pollution control districts and air quality management districts with the primary responsibility for the control of air pollution from all sources other than vehicular sources. Existing law requires the state board to inventory sources of air pollution within the air basins of the state, determine the kinds and quantity of air pollutants, and monitor air pollutants in cooperation with districts and other agencies.

Existing law requires the state board to adopt standards of ambient air quality for each air basin in consideration of the public health, safety, and welfare, including, but not limited to, health, illness, irritation to the senses, aesthetic value, interference with visibility, and effects on the economy. Existing law authorizes these standards to vary from one air basin to another.

This bill would require the state board, in consultation with specified entities, to develop, as provided, a response framework that establishes best practices and guidance for addressing fugitive and natural sources of hydrogen sulfide gas and for community preparation and response to hydrogen sulfide exposure events originating from these sources. The bill would require the state board, in developing the response framework, to conduct at least 3 public workshops, including at least one located in the Tijuana River Valley region, at least one located in the Salton Sea region, and at least one selected in consultation with a community that has experienced significant hydrogen sulfide exposure. The bill would require the Office of Environmental Health Hazard Assessment to update the acute and chronic reference exposure levels for hydrogen sulfide and to develop additional health guidance values for hydrogen sulfide, if the need is identified by the state board, in consultation with the office, during development of the response framework.

Existing law generally designates the State Air Resources Board as the state agency with the primary responsibility for the control of vehicular air pollution, and designates air pollution control districts and air quality management districts with the primary responsibility for the control of air pollution from all sources other than vehicular sources. Existing law requires the state board to inventory sources of air pollution within the air basins of the state, determine the kinds and quantity of air pollutants, and monitor air pollutants in cooperation with districts and other agencies.

Existing law requires the state board to adopt standards of ambient air quality for each air basin in consideration of the public health, safety, and welfare, including, but not limited to, health, illness, irritation to the senses, aesthetic value, interference with visibility, and effects on the economy. Existing law authorizes these standards to vary from one air basin to another.

This bill would require the state board, in consultation with specified entities, to develop, as provided, a response framework that establishes best practices and guidance for addressing fugitive and natural sources of hydrogen sulfide gas and for community preparation and response to hydrogen sulfide exposure events originating from these sources. The bill would require the state board, in developing the response framework, to conduct at least 3 public workshops, including at least one located in the Tijuana River Valley region, at least one located in the Salton Sea region, and at least one selected in consultation with a community that has experienced significant hydrogen sulfide exposure. The bill would require the Office of Environmental Health Hazard Assessment to update the acute and chronic reference exposure levels for hydrogen sulfide and to develop additional health guidance values for hydrogen sulfide, if the need is identified by the state board, in consultation with the office, during development of the response framework.

Existing law generally designates the State Air Resources Board as the state agency with the primary responsibility for the control of vehicular air pollution, and designates air pollution control districts and air quality management districts with the primary responsibility for the control of air pollution from all sources other than vehicular sources. Existing law requires the state board to inventory sources of air pollution within the air basins of the state, determine the kinds and quantity of air pollutants, and monitor air pollutants in cooperation with districts and other agencies.

Existing law requires the state board to adopt standards of ambient air quality for each air basin in consideration of the public health, safety, and welfare, including, but not limited to, health, illness, irritation to the senses, aesthetic value, interference with visibility, and effects on the economy. Existing law authorizes these standards to vary from one air basin to another. Existing law requires the standards relating to health effects to be based upon the recommendations of the Office of Environmental Health Hazard Assessment.

This bill would require, on or before January 1, 2030, the office to develop health-based threshold levels for hydrogen sulfide. The bill would further authorize the office to develop threshold levels for additional air pollutants with the considerations specified for hydrogen sulfide upon an appropriation for this purpose from the Legislature. The bill would require the office require the state board, in consultation with specified entities, to develop, as provided, a response framework that establishes best practices and guidance for addressing fugitive and natural sources of hydrogen sulfide gas and for community preparation and response to hydrogen sulfide exposure events originating from these sources. The bill would require the state board, in developing the response framework, to conduct at least 3 public workshops, including at least one located in the Tijuana River Valley region, at least one located in the Salton Sea region, and at least one selected in consultation with a community that has experienced significant hydrogen sulfide exposure.

Existing law generally designates the State Air Resources Board as the state agency with the primary responsibility for the control of vehicular air pollution, and designates air pollution control districts and air quality management districts with the primary responsibility for the control of air pollution from all sources other than vehicular sources. Existing law requires the state board to inventory sources of air pollution within the air basins of the state, determine the kinds and quantity of air pollutants, and monitor air pollutants in cooperation with districts and other agencies.

Existing sales and use tax laws impose taxes on retailers measured by the gross receipts from the sale of tangible personal property sold at retail in this state, or on the storage, use, or other consumption in this state of tangible personal property purchased from a retailer for storage, use, or other consumption in this state, and provide various exemptions from the taxes imposed by those laws.

This bill would, on and after January 1, 2025, 2026, provide a partial exemption from those taxes with respect to the gross receipts from the sale, storage, use, installation, assembly, repair, maintenance, or other consumption of data center equipment, as defined, used at or for the benefit of a certified data center facility, as defined. The bill would require a data center facility to meet specified requirements in order to receive certification from the California Department of Tax and Fee Administration, including requirements relating to job creation, investment, and renewable energy procurement requirements. The bill would require the department to revoke certification where a data center facility obtains certification and subsequently fails to meet these requirements after reasonable opportunity for the data center facility to cure noncompliance, as provided.

The Bradley-Burns Uniform Local Sales and Use Tax Law authorizes counties and cities to impose local sales and use taxes in conformity with the Sales and Use Tax Law, and existing laws authorize districts, as specified, to impose transactions and use taxes in accordance with the Transactions and Use Tax Law, which generally conforms to the Sales and Use Tax Law. Amendments to the Sales and Use Tax Law are automatically incorporated into the local tax laws.

This bill would provide that the partial exemption created by the bill does not apply to local sales and use taxes or transactions and use taxes.

Existing law imposes or dedicates certain state sales and use tax rates for local funding, including through the Local Revenue Fund 2011.

This bill would provide that the exemption created by the bill does not apply to those state sales and use tax rates imposed or dedicated for local government funding, including those rates for which revenues are deposited into the Local Revenue Fund 2011.

Existing law requires any bill authorizing a new tax expenditure to contain, among other things, specific goals that the tax expenditure will achieve, detailed performance indicators, and data collection requirements.

This bill would include additional information required for any bill authorizing a new tax expenditure.

This bill would take effect immediately as a tax levy.

Existing sales and use tax laws impose taxes on retailers measured by the gross receipts from the sale of tangible personal property sold at retail in this state, or on the storage, use, or other consumption in this state of tangible personal property purchased from a retailer for storage, use, or other consumption in this state, and provide various exemptions from the taxes imposed by those laws.

This bill would, on and after January 1, 2025, provide a partial exemption from those taxes with respect to the gross receipts from the sale, storage, use, installation, assembly, repair, maintenance, or other consumption of data center equipment, as defined, used at or for the benefit of a certified data center facility, as defined. The bill would require a data center facility to meet specified requirements in order to receive certification from the California Department of Tax and Fee Administration, including requirements relating to job creation, investment, and renewable energy procurement requirements. The bill would require the department to revoke certification where a data center facility obtains certification and subsequently fails to meet these requirements after reasonable opportunity for the data center facility to cure noncompliance, as provided.

The Bradley-Burns Uniform Local Sales and Use Tax Law authorizes counties and cities to impose local sales and use taxes in conformity with the Sales and Use Tax Law, and existing laws authorize districts, as specified, to impose transactions and use taxes in accordance with the Transactions and Use Tax Law, which generally conforms to the Sales and Use Tax Law. Amendments to the Sales and Use Tax Law are automatically incorporated into the local tax laws.

This bill would provide that the partial exemption created by the bill does not apply to local sales and use taxes or transactions and use taxes.

Existing law imposes or dedicates certain state sales and use tax rates for local funding, including through the Local Revenue Fund 2011.

This bill would provide that the exemption created by the bill does not apply to those state sales and use tax rates imposed or dedicated for local government funding, including those rates for which revenues are deposited into the Local Revenue Fund 2011.

Existing law requires any bill authorizing a new tax expenditure to contain, among other things, specific goals that the tax expenditure will achieve, detailed performance indicators, and data collection requirements.

This bill would include additional information required for any bill authorizing a new tax expenditure.

This bill would take effect immediately as a tax levy.

 UNFINISHED BUSINESS  

Bill No: SB 58

Author: Padilla (D), et al.

Amended: 8/13/26

Vote: 21

SENATE ENVIRONMENTAL QUALITY COMMITTEE: 7-0, 1/13/26

AYES: Blakespear, Valladares, Dahle, Gonzalez, Menjivar, Pérez, Reyes

NO VOTE RECORDED: Hurtado

SENATE APPROPRIATIONS COMMITTEE: 7-0, 1/22/26

AYES: Caballero, Seyarto, Cabaldon, Dahle, Grayson, Richardson, Wahab

SENATE FLOOR: 39-0, 1/26/26

AYES: Allen, Alvarado-Gil, Archuleta, Arreguín, Ashby, Becker, Blakespear, Cabaldon, Caballero, Cervantes, Choi, Cortese, Dahle, Durazo, Grayson, Grove, Hurtado, Jones, Laird, Limón, McGuire, McNerney, Menjivar, Niello, Ochoa Bogh, Padilla, Pérez, Reyes, Richardson, Rubio, Seyarto, Smallwood-Cuevas, Stern, Strickland, Umberg, Valladares, Wahab, Weber Pierson, Wiener

NO VOTE RECORDED: Gonzalez

ASSEMBLY FLOOR: 78-0, 8/27/26 - See last page for vote

SUBJECT: Air quality: standard: hydrogen sulfide

SOURCE: Author

DIGEST:

This bill requires the California Air Resources Board (CARB) to develop a response framework to address hydrogen sulfide gas, as described, and the Office of Environmental Health Hazard Assessment (OEHHA) to update and develop health-based levels for hydrogen sulfide, if necessary.

Assembly Amendments

require CARB to develop a response framework to address fugitive and natural sources of hydrogen sulfide gas and require OEHHA to update the acute and chronic reference exposure levels for hydrogen sulfide and determine additional health guidance values during the development of the response framework.

ANALYSIS:

Existing federal law:

1. The federal Clean Air Act (CAA) and its implementing regulations set National Ambient Air Quality Standard (NAAQS) for six criteria pollutants, designate air basins that do not achieve NAAQS as nonattainment, and require states with nonattainment areas to submit a State Implementation Plan (SIP) detailing how they will achieve compliance with NAAQS. (42 U.S.C. 7401 et seq.)

Existing state law:

1. Establishes OEHHA under the California Environmental Protection Agency and authorizes OEHHA to perform activities relating to the assessment of human health risks of chemicals, toxicology, or scientific consultation. (Health & Safety Code (HSC) § 59000 et seq.)
2. Establishes CARB as the air pollution control agency in California and requires CARB, among other things, to control emissions from a wide array of mobile sources and coordinate with local air districts to control emissions from stationary sources in order to implement the CAA. (Health and Safety Code (HSC) § 39000 et seq.)
3. Requires CARB to adopt ambient air quality standards for each air basin in consideration of the public health, safety, and welfare, and based upon the recommendations of OEHHA. (HSC § 39606(a)(2))
4. Authorizes CARB or local air districts to adopt regulations to control pollutants associated with state ambient air quality standards, including hydrogen sulfide. (HSC § 40926)
5. Required CARB, in consultation with OEHHA, to review all existing health-based ambient air quality standards, including hydrogen sulfide, to determine whether they adequately protect the health of the public, including infants and children, before December 31, 2000. (HSC § 39606(d))
6. Requires, subject to the powers and duties of CARB, local air districts to adopt and enforce rules and regulations to achieve and maintain the state and federal air quality standards in all areas affected by emission sources under their jurisdiction, and to enforce all applicable provisions of state and federal law. (HSC § 40001)
7. Authorizes local air district rules and regulations to provide for the prevention and abatement of air pollution episodes which cause discomfort or health risks to a significant number of persons. (HSC § 40001(b))
8. Authorizes local air districts to sponsor, coordinate, and promote projects that will lead to the prevention, mitigation, or cure of the adverse effects of air pollution, including the adverse health effects of air pollution. (HSC § 40004)

This bill:

1. Defines “fugitive source” to mean any source of emissions of hydrogen sulfide gas that is not currently regulated as a stationary source by a local air pollution control district or air quality management district.
2. Defines “natural source” to mean a source of hydrogen sulfide occurring in nature as a result of environmental circumstances that is not regulated as a stationary source by a local air pollution control district or air quality management district.
3. Requires CARB to develop a response framework that establishes best practices and guidance for addressing fugitive and natural sources of hydrogen sulfide gas and for community preparation and response to hydrogen sulfide exposure events originating from these sources in consultation with specified agencies and entities.
4. Requires the response framework to do all of the following:
   1. Consider cross-media releases;
   2. Develop integrated, multiagency approaches to identify and address fugitive and natural sources;
   3. Develop methods for reducing identified fugitive and natural sources of hydrogen sulfide gas in impacted communities;
   4. Consider threshold levels, including the acute and chronic reference exposure levels developed by OEHHA, and corresponding actions and evaluate the need for additional threshold levels, averaging durations, and corresponding actions for sub-chronic exposures or short-term exposures;
   5. Develop best practices for measuring hydrogen sulfide levels in air and using monitoring data;
   6. Consider the influence of local and regional climates, and outdoor and indoor settings, on exposure; and
   7. Include an estimate of resources needed for its implementation by local and state agencies.
5. Requires OEHHA to update the acute and chronic reference exposure levels for hydrogen sulfide and develop additional health guidance values for hydrogen sulfide, if the need is identified by CARB, in consultation with OEHHA, during development of the response framework.
6. Requires CARB, in developing the response framework, to conduct at least three public workshops located in all of the following:
   1. At least one in the Tijuana River Valley region;
   2. At least one in the Salton Sea region; and
   3. At least one selected in consultation with a community that has experienced significant hydrogen sulfide exposure.
7. Makes related findings and declarations.

Background

Hydrogen sulfide. Hydrogen sulfide, commonly associated with sewage, landfills, geothermal fields, and oil and natural gas extraction, is a toxic gas that produces a foul odor. Hydrogen sulfide is known to cause negative respiratory and neurological impacts at the acute exposure level, and while epidemiological information for chronic effects is limited, some studies suggest chronic exposure levels may be associated with ocular, cardiovascular, respiratory, and neurological impacts.^{[1],[2],[3],[4]}

The odd ones out. Unlike the emissions from entities that CARB and local air districts regulate, there have been incidents of air emissions across the state that do not have a clear responsible party, but may far exceed established standards and have significant impacts on neighboring communities. The two situations highlighted by this bill are examples of these “orphan incidents”:

• 1. Tijuana River Valley. Near the California-Mexico border, raw sewage from Tijuana crosses into San Diego County polluting the Tijuana River Valley with industrial chemicals, pesticides, and trash.^[5],[6] As this transboundary pollution meanders through the valley, it generates hydrogen sulfide emissions and local scientists and communities have raised alarms about a particular emission site on Saturn Blvd, infamously known as the “hot spot”.^[7] A constricted culvert under Saturn Blvd accelerates the untreated wastewater, generating turbulence and emitting hydrogen sulfide. When the wastewater is not diverted in Mexico, hydrogen sulfide has been detected at 2100 ppb (1-hour average), which is 70 times the nuisance standard, and frequently spikes depending on the flow rate of the sewage. Local scientists have demonstrated that averaging the hydrogen sulfide data over 1 hour to compare to the 30-ppb standard does not capture exceedances that occur within minutes and are suspected to have negative public health implications. The community has called for standards that consider different averaging times to capture these spikes and subsequent public notice and response.
  2. Salton Sea. Located in Riverside and Imperial counties, the Salton Sea tends to be a major source of hydrogen sulfide emissions due to a large influx of nutrients through agricultural runoff and the declining water levels, which increase the sea’s ability to mix.^{[8],[9],[10],[11]} With summer conditions, monitoring efforts have shown that hydrogen sulfide frequently exceeds the 30 ppb standard, for hundreds of hours over the course of the season.^[12] The humid climate of the region anecdotally exacerbates health effects and the current standard does not take humidity into account. These emissions impact communities already overburdened and suffering respiratory impacts from other emissions originating from the progressively declining Salton Sea, such as aerosolized seawater containing toxins and particulate matter released from the exposed seabed.⁹

Differences between monitoring techniques and deployment locations between local agencies and external groups have highlighted discrepancies in exceedances of the hydrogen sulfide standard.¹² While there are jurisdictional limitations and particular considerations that influence where air quality management districts deploy their monitors, universities and non-governmental organizations have called for more comprehensive monitoring that factors in wind direction.^9,12,[13]

These incidents fall outside existing regulatory frameworks because attainment plans, and any subsequent action, may not be applicable to sources without specific and identifiable responsible parties. This bill addresses this regulatory gap by requiring CARB to develop a response framework for addressing such incidents and OEHHA to develop additional health guidance values to complement mechanisms in the response framework, if necessary.

Comments

Purpose of Bill. According to the author, “For generations, families in some of the most economically strained parts of the state have suffered from millions of gallons of sewage and pollution flowing through the Tijuana River and emissions from the Salton Sea. This pollution has been harming our community for decades and yet our air quality standards haven’t been updated in nearly half a century. It is unacceptable that the regulatory standard monitoring the very air our families breathe is so woefully out of date, leaving communities at risk. Making this critical change is a long overdue step towards addressing an issue that has been allowed to fester for decades. It is critical that Sacramento finally act to help our community.”

FISCAL EFFECT: Appropriation: No Fiscal Com.: Yes Local: No

According to the Assembly Appropriations Committee:

1. CARB estimates costs of $1.8 million in fiscal year (FY) 2027-28 for about six new positions, contract dollars, and equipment, followed by ongoing annual costs of $1.3 million in FY 2028-29 and ongoing (Air Pollution Control Fund).

Specifically, CARB expects to serve as a subject matter expert on H₂S emission sources, health effects from ambient exposures, cross-media releases, exposure mitigation strategies, health-based Reference Exposure Levels (RELs), and health- and nuisance-based standards; draft the required framework and manage subsequent updates; consult and coordinate with a diverse group of stakeholders; lead public workshops and engage in targeted outreach to affected communities; develop region-specific and multilingual educational resources on the response framework in coordination with community-based organizations; serve as the technical lead on developing monitoring plans; serve as the response and outreach lead for incident operations; provide technical support and deliver guidance and training to local air districts and health agencies on monitoring and response planning; and various other tasks.

As part of the costs outlined above, CARB anticipates needing portable field instruments as well as air monitoring equipment to respond to planned and unplanned releases, spikes in air quality, and emergency incidents.

1. The Office of Environmental Health Hazard Assessment (OEHHA) estimates ongoing annual costs of approximately $423,000 for two positions, a one-time contracting cost of $400,000, and ongoing annual contracting costs of $150,000 (General Fund). While the bill directs CARB to develop a response framework to address sources of H₂S, in practice, CARB is very likely to consult with OEHHA in developing the required framework. OEHHA has previously developed RELs for H₂S, which are used by CARB, local air districts, and others when evaluating emissions from facilities, permitting, and conducting health risk assessments. Accordingly, OEHHA expects to lend its technical expertise to CARB in the development and updating of H₂S thresholds, participate in the required public workshops, and rely on a contractor for some of its technical support needs.
2. OES and CDPH anticipate minor and absorbable costs to consult with CARB.
3. Costs of an unknown, likely absorbable, amount for the regional water quality control boards to consult with CARB.

SUPPORT: (Verified 8/27/26)

Alianza Coachella Valley
Alliance San Diego
Azul
Cactustocloud Institute
City of Imperial
City of Imperial Beach
City of Indian Wells
City of Indio
City of Needles
Cleanearth4kids.org
Coachella Valley Association of Governments
Coalition for Clean Air
Coronado Democratic Club
Desert Care Network
Desert Recreation District
Environmental Health Coalition
Imperial Valley Equity & Justice Coalition
Imperial Valley Healthcare District
LA Cooperativa Campesina De California
Latino Outdoors
Leadership Counsel for Justice and Accountability
Loma Linda University Adventist Health Sciences Center and its Affiliated Entities
Los Amigos De LA Comunidad, INC.
Outdoor Outreach
Palm Desert Area Chamber of Commerce
San Diego for Every Child
San Diego; County of
Sierra Club
Sierra Service Project
Solana Beach Eco Rotary Club
Surfrider Foundation
Sustainable Socal
The Border Group
Tijuana River Coaliton
Un Mar De Colores
Wildcoast
YMCA of San Diego County

29 Individuals

OPPOSITION: (Verified 8/27/2026)

1 Individual

ASSEMBLY FLOOR: 78-0, 8/27/26

AYES: Addis, Aguiar-Curry, Ahrens, Alanis, Alvarez, Arambula, Ávila Farías, Bains, Bauer-Kahan, Bennett, Berman, Boerner, Bonta, Bryan, Calderon, Caloza, Carrillo, Castillo, Chen, Connolly, Davies, DeMaio, Dixon, Elhawary, Ellis, Flora, Fong, Gabriel, Garcia, Gipson, Jeff Gonzalez, Mark González, Hadwick, Haney, Harabedian, Hart, Hoover, Irwin, Jackson, Johnson, Kalra, Krell, Lackey, Lee, Lowenthal, Macedo, Muratsuchi, Nguyen, Ortega, Pacheco, Papan, Patel, Patterson, Pellerin, Petrie-Norris, Quirk-Silva, Ramos, Ransom, Celeste Rodriguez, Michelle Rodriguez, Rogers, Blanca Rubio, Sanchez, Schiavo, Schultz, Sharp-Collins, Solache, Soria, Stefani, Ta, Tangipa, Valencia, Wallis, Ward, Wicks, Wilson, Zbur, Rivas

NO VOTE RECORDED: McKinnor

Prepared by: Taylor McKie / E.Q. / (916) 651-4108

9/16/26 14:40:31

**** END ****

1. Office of Environmental Health and Hazard Assessment. (2000). Chronic Toxicity Summary: Hydrogen Sulfide. ↑

2. Office of Environmental Health and Hazard Assessment. (2008). Acute Toxicity Summary: Hydrogen Sulfide. ↑

3. Batterman, S., et. al. (2023). Low level exposure to hydrogen sulfide: a review of emissions, community exposure, health effects, and exposure guidelines. ↑

4. Nuvolone, D., et. al. (2019). Health effects associated with chronic exposure to low-level hydrogen sulfide from geothermoelectric power plants. ↑

5. McLamb, F., et. al. (2024). Evidence of transboundary movement of chemicals from Mexico to the U.S. in Tijuana River Estuary sediments. ↑

6. Cooper, A., et. al. (2025). Identifying wastewater chemicals in coastal aerosols. ↑

7. Rico, B., et. al. (2025). Heavily polluted Tijuana River drives regional air quality crisis. ↑

8. Reese, B., et. al. (2008). Hydrogen sulfide production and volatilization in a polymictic eutrophic saline lake, Salton Sea, California. ↑

9. Centeno, D., et. al. (2025). Hypereutrophication, Hydrogen Sulfide, and Environmental Injustices: Mechanisms and Knowledge Gaps at the Salton Sea. ↑

10. Márquez, C., et. al. (2025). Inadequate Government-Led Water-Quality Monitoring Hinders Improvement Efforts in the Salton Sea. ↑

11. Wilson, J. (2024). This stinks: Salton Sea now emitting bad smells year round. Here’s why. ↑

12. Márquez, C., et. al. (2025). Salton Sea Exceedances of California’s Air Quality Standards Highlight Governance Gaps and Monitoring Needs. ↑

13. Wilson, J. (2025). Study: Salton Sea is emitting foul gas at levels worse than official monitors show. ↑

 UNFINISHED BUSINESS  

Bill No: SB 58

Author: Padilla (D), et al.

Amended: 8/13/26

Vote: 21

SENATE ENVIRONMENTAL QUALITY COMMITTEE: 7-0, 1/13/26

AYES: Blakespear, Valladares, Dahle, Gonzalez, Menjivar, Pérez, Reyes

NO VOTE RECORDED: Hurtado

SENATE APPROPRIATIONS COMMITTEE: 7-0, 1/22/26

AYES: Caballero, Seyarto, Cabaldon, Dahle, Grayson, Richardson, Wahab

SENATE FLOOR: 39-0, 1/26/26

AYES: Allen, Alvarado-Gil, Archuleta, Arreguín, Ashby, Becker, Blakespear, Cabaldon, Caballero, Cervantes, Choi, Cortese, Dahle, Durazo, Grayson, Grove, Hurtado, Jones, Laird, Limón, McGuire, McNerney, Menjivar, Niello, Ochoa Bogh, Padilla, Pérez, Reyes, Richardson, Rubio, Seyarto, Smallwood-Cuevas, Stern, Strickland, Umberg, Valladares, Wahab, Weber Pierson, Wiener

NO VOTE RECORDED: Gonzalez

ASSEMBLY FLOOR: Passed, 8/27/26

SUBJECT: Air quality: standard: hydrogen sulfide

SOURCE: Author

DIGEST:

This bill requires the California Air Resources Board (CARB) to develop a response framework to address hydrogen sulfide gas, as described, and the Office of Environmental Health Hazard Assessment (OEHHA) to update and develop health-based levels for hydrogen sulfide, if necessary.

Assembly Amendments

require CARB to develop a response framework to address fugitive and natural sources of hydrogen sulfide gas and require OEHHA to update the acute and chronic reference exposure levels for hydrogen sulfide and determine additional health guidance values during the development of the response framework.

ANALYSIS:

Existing federal law:

1. The federal Clean Air Act (CAA) and its implementing regulations set National Ambient Air Quality Standard (NAAQS) for six criteria pollutants, designate air basins that do not achieve NAAQS as nonattainment, and require states with nonattainment areas to submit a State Implementation Plan (SIP) detailing how they will achieve compliance with NAAQS. (42 U.S.C. 7401 et seq.)

Existing state law:

1. Establishes OEHHA under the California Environmental Protection Agency and authorizes OEHHA to perform activities relating to the assessment of human health risks of chemicals, toxicology, or scientific consultation. (Health & Safety Code (HSC) § 59000 et seq.)
2. Establishes CARB as the air pollution control agency in California and requires CARB, among other things, to control emissions from a wide array of mobile sources and coordinate with local air districts to control emissions from stationary sources in order to implement the CAA. (Health and Safety Code (HSC) § 39000 et seq.)
3. Requires CARB to adopt ambient air quality standards for each air basin in consideration of the public health, safety, and welfare, and based upon the recommendations of OEHHA. (HSC § 39606(a)(2))
4. Authorizes CARB or local air districts to adopt regulations to control pollutants associated with state ambient air quality standards, including hydrogen sulfide. (HSC § 40926)
5. Required CARB, in consultation with OEHHA, to review all existing health-based ambient air quality standards, including hydrogen sulfide, to determine whether they adequately protect the health of the public, including infants and children, before December 31, 2000. (HSC § 39606(d))
6. Requires, subject to the powers and duties of CARB, local air districts to adopt and enforce rules and regulations to achieve and maintain the state and federal air quality standards in all areas affected by emission sources under their jurisdiction, and to enforce all applicable provisions of state and federal law. (HSC § 40001)
7. Authorizes local air district rules and regulations to provide for the prevention and abatement of air pollution episodes which cause discomfort or health risks to a significant number of persons. (HSC § 40001(b))
8. Authorizes local air districts to sponsor, coordinate, and promote projects that will lead to the prevention, mitigation, or cure of the adverse effects of air pollution, including the adverse health effects of air pollution. (HSC § 40004)

This bill:

1. Defines “fugitive source” to mean any source of emissions of hydrogen sulfide gas that is not currently regulated as a stationary source by a local air pollution control district or air quality management district.
2. Defines “natural source” to mean a source of hydrogen sulfide occurring in nature as a result of environmental circumstances that is not regulated as a stationary source by a local air pollution control district or air quality management district.
3. Requires CARB to develop a response framework that establishes best practices and guidance for addressing fugitive and natural sources of hydrogen sulfide gas and for community preparation and response to hydrogen sulfide exposure events originating from these sources in consultation with specified agencies and entities.
4. Requires the response framework to do all of the following:
   1. Consider cross-media releases;
   2. Develop integrated, multiagency approaches to identify and address fugitive and natural sources;
   3. Develop methods for reducing identified fugitive and natural sources of hydrogen sulfide gas in impacted communities;
   4. Consider threshold levels, including the acute and chronic reference exposure levels developed by OEHHA, and corresponding actions and evaluate the need for additional threshold levels, averaging durations, and corresponding actions for sub-chronic exposures or short-term exposures;
   5. Develop best practices for measuring hydrogen sulfide levels in air and using monitoring data;
   6. Consider the influence of local and regional climates, and outdoor and indoor settings, on exposure; and
   7. Include an estimate of resources needed for its implementation by local and state agencies.
5. Requires OEHHA to update the acute and chronic reference exposure levels for hydrogen sulfide and develop additional health guidance values for hydrogen sulfide, if the need is identified by CARB, in consultation with OEHHA, during development of the response framework.
6. Requires CARB, in developing the response framework, to conduct at least three public workshops located in all of the following:
   1. At least one in the Tijuana River Valley region;
   2. At least one in the Salton Sea region; and
   3. At least one selected in consultation with a community that has experienced significant hydrogen sulfide exposure.
7. Makes related findings and declarations.

Background

Hydrogen sulfide. Hydrogen sulfide, commonly associated with sewage, landfills, geothermal fields, and oil and natural gas extraction, is a toxic gas that produces a foul odor. Hydrogen sulfide is known to cause negative respiratory and neurological impacts at the acute exposure level, and while epidemiological information for chronic effects is limited, some studies suggest chronic exposure levels may be associated with ocular, cardiovascular, respiratory, and neurological impacts.^{[1],[2],[3],[4]}

The odd ones out. Unlike the emissions from entities that CARB and local air districts regulate, there have been incidents of air emissions across the state that do not have a clear responsible party, but may far exceed established standards and have significant impacts on neighboring communities. The two situations highlighted by this bill are examples of these “orphan incidents”:

• 1. Tijuana River Valley. Near the California-Mexico border, raw sewage from Tijuana crosses into San Diego County polluting the Tijuana River Valley with industrial chemicals, pesticides, and trash.^[5],[6] As this transboundary pollution meanders through the valley, it generates hydrogen sulfide emissions and local scientists and communities have raised alarms about a particular emission site on Saturn Blvd, infamously known as the “hot spot”.^[7] A constricted culvert under Saturn Blvd accelerates the untreated wastewater, generating turbulence and emitting hydrogen sulfide. When the wastewater is not diverted in Mexico, hydrogen sulfide has been detected at 2100 ppb (1-hour average), which is 70 times the nuisance standard, and frequently spikes depending on the flow rate of the sewage. Local scientists have demonstrated that averaging the hydrogen sulfide data over 1 hour to compare to the 30-ppb standard does not capture exceedances that occur within minutes and are suspected to have negative public health implications. The community has called for standards that consider different averaging times to capture these spikes and subsequent public notice and response.
  2. Salton Sea. Located in Riverside and Imperial counties, the Salton Sea tends to be a major source of hydrogen sulfide emissions due to a large influx of nutrients through agricultural runoff and the declining water levels, which increase the sea’s ability to mix.^{[8],[9],[10],[11]} With summer conditions, monitoring efforts have shown that hydrogen sulfide frequently exceeds the 30 ppb standard, for hundreds of hours over the course of the season.^[12] The humid climate of the region anecdotally exacerbates health effects and the current standard does not take humidity into account. These emissions impact communities already overburdened and suffering respiratory impacts from other emissions originating from the progressively declining Salton Sea, such as aerosolized seawater containing toxins and particulate matter released from the exposed seabed.⁹

Differences between monitoring techniques and deployment locations between local agencies and external groups have highlighted discrepancies in exceedances of the hydrogen sulfide standard.¹² While there are jurisdictional limitations and particular considerations that influence where air quality management districts deploy their monitors, universities and non-governmental organizations have called for more comprehensive monitoring that factors in wind direction.^9,12,[13]

These incidents fall outside existing regulatory frameworks because attainment plans, and any subsequent action, may not be applicable to sources without specific and identifiable responsible parties. This bill addresses this regulatory gap by requiring CARB to develop a response framework for addressing such incidents and OEHHA to develop additional health guidance values to complement mechanisms in the response framework, if necessary.

Comments

Purpose of Bill. According to the author, “For generations, families in some of the most economically strained parts of the state have suffered from millions of gallons of sewage and pollution flowing through the Tijuana River and emissions from the Salton Sea. This pollution has been harming our community for decades and yet our air quality standards haven’t been updated in nearly half a century. It is unacceptable that the regulatory standard monitoring the very air our families breathe is so woefully out of date, leaving communities at risk. Making this critical change is a long overdue step towards addressing an issue that has been allowed to fester for decades. It is critical that Sacramento finally act to help our community.”

FISCAL EFFECT: Appropriation: No Fiscal Com.: Yes Local: No

According to the Assembly Appropriations Committee:

1. CARB estimates costs of $1.8 million in fiscal year (FY) 2027-28 for about six new positions, contract dollars, and equipment, followed by ongoing annual costs of $1.3 million in FY 2028-29 and ongoing (Air Pollution Control Fund).

Specifically, CARB expects to serve as a subject matter expert on H₂S emission sources, health effects from ambient exposures, cross-media releases, exposure mitigation strategies, health-based Reference Exposure Levels (RELs), and health- and nuisance-based standards; draft the required framework and manage subsequent updates; consult and coordinate with a diverse group of stakeholders; lead public workshops and engage in targeted outreach to affected communities; develop region-specific and multilingual educational resources on the response framework in coordination with community-based organizations; serve as the technical lead on developing monitoring plans; serve as the response and outreach lead for incident operations; provide technical support and deliver guidance and training to local air districts and health agencies on monitoring and response planning; and various other tasks.

As part of the costs outlined above, CARB anticipates needing portable field instruments as well as air monitoring equipment to respond to planned and unplanned releases, spikes in air quality, and emergency incidents.

1. The Office of Environmental Health Hazard Assessment (OEHHA) estimates ongoing annual costs of approximately $423,000 for two positions, a one-time contracting cost of $400,000, and ongoing annual contracting costs of $150,000 (General Fund). While the bill directs CARB to develop a response framework to address sources of H₂S, in practice, CARB is very likely to consult with OEHHA in developing the required framework. OEHHA has previously developed RELs for H₂S, which are used by CARB, local air districts, and others when evaluating emissions from facilities, permitting, and conducting health risk assessments. Accordingly, OEHHA expects to lend its technical expertise to CARB in the development and updating of H₂S thresholds, participate in the required public workshops, and rely on a contractor for some of its technical support needs.
2. OES and CDPH anticipate minor and absorbable costs to consult with CARB.
3. Costs of an unknown, likely absorbable, amount for the regional water quality control boards to consult with CARB.

SUPPORT: (Verified 8/27/26)

Alianza Coachella Valley
Alliance San Diego
Azul
Cactustocloud Institute
City of Imperial
City of Imperial Beach
City of Indian Wells
City of Indio
City of Needles
Cleanearth4kids.org
Coachella Valley Association of Governments
Coalition for Clean Air
Coronado Democratic Club
Desert Care Network
Desert Recreation District
Environmental Health Coalition
Imperial Valley Equity & Justice Coalition
Imperial Valley Healthcare District
LA Cooperativa Campesina De California
Latino Outdoors
Leadership Counsel for Justice and Accountability
Loma Linda University Adventist Health Sciences Center and its Affiliated Entities
Los Amigos De LA Comunidad, INC.
Outdoor Outreach
Palm Desert Area Chamber of Commerce
San Diego for Every Child
San Diego; County of
Sierra Club
Sierra Service Project
Solana Beach Eco Rotary Club
Surfrider Foundation
Sustainable Socal
The Border Group
Tijuana River Coaliton
Un Mar De Colores
Wildcoast
YMCA of San Diego County

29 Individuals

OPPOSITION: (Verified 8/27/2026)

1 Individual

Prepared by: Taylor McKie / E.Q. / (916) 651-4108

8/27/26 16:26:12

**** END ****

1. Office of Environmental Health and Hazard Assessment. (2000). Chronic Toxicity Summary: Hydrogen Sulfide. ↑

2. Office of Environmental Health and Hazard Assessment. (2008). Acute Toxicity Summary: Hydrogen Sulfide. ↑

3. Batterman, S., et. al. (2023). Low level exposure to hydrogen sulfide: a review of emissions, community exposure, health effects, and exposure guidelines. ↑

4. Nuvolone, D., et. al. (2019). Health effects associated with chronic exposure to low-level hydrogen sulfide from geothermoelectric power plants. ↑

5. McLamb, F., et. al. (2024). Evidence of transboundary movement of chemicals from Mexico to the U.S. in Tijuana River Estuary sediments. ↑

6. Cooper, A., et. al. (2025). Identifying wastewater chemicals in coastal aerosols. ↑

7. Rico, B., et. al. (2025). Heavily polluted Tijuana River drives regional air quality crisis. ↑

8. Reese, B., et. al. (2008). Hydrogen sulfide production and volatilization in a polymictic eutrophic saline lake, Salton Sea, California. ↑

9. Centeno, D., et. al. (2025). Hypereutrophication, Hydrogen Sulfide, and Environmental Injustices: Mechanisms and Knowledge Gaps at the Salton Sea. ↑

10. Márquez, C., et. al. (2025). Inadequate Government-Led Water-Quality Monitoring Hinders Improvement Efforts in the Salton Sea. ↑

11. Wilson, J. (2024). This stinks: Salton Sea now emitting bad smells year round. Here’s why. ↑

12. Márquez, C., et. al. (2025). Salton Sea Exceedances of California’s Air Quality Standards Highlight Governance Gaps and Monitoring Needs. ↑

13. Wilson, J. (2025). Study: Salton Sea is emitting foul gas at levels worse than official monitors show. ↑

SENATE THIRD READING

STR Bill Id:SB 58

Author:(Padilla)

As Amended Ver:August 13, 2026

Majority vote

SUMMARY

Requires the Air Resources Board (ARB) to develop a response framework to address fugitive and natural sources of hydrogen sulfide (H₂S).

Major Provisions

1. Requires ARB, in consultation with local air districts, the Office of Environmental Health Hazard Assessment (OEHHA), the Office of Emergency Services, the State Department of Public Health, regional water quality control boards or other local or regional authorities, local environmental and public health agencies, universities and academic institutions, affected tribal governments, and community-based organizations, to develop a response framework that establishes best practices and guidance for addressing fugitive and natural sources of H₂S gas and for community preparation and response to H₂S exposure events originating from these sources.
2. Requires the response framework to:
   1. Consider cross-media releases.
   2. Develop integrated, multiagency approaches to identify and address fugitive and natural sources.
   3. Develop methods for reducing identified fugitive and natural sources of H₂S gas in impacted communities.
   4. Consider threshold levels and corresponding actions, and evaluate the need for additional threshold levels, averaging durations, and corresponding actions for subchronic or short-term exposures.
   5. Develop best practices for measuring H₂S levels in air and using monitoring data.
   6. Consider the influence of local and regional climates, and outdoor and indoor settings, on exposure.
   7. Consider how responses may differ for shorter term incidents compared to conditions that may be expected to persist for longer periods.
   8. Include an estimate of resources needed for its implementation by local and state agencies.
3. Requires OEHHA to update reference exposure levels, and develop additional health guidance values, for H₂S if the need is identified by ARB, in consultation with OEHHA, during the development of the response framework.
4. Requires ARB to conduct at least three public workshops located in the following:
   1. At least one in the Tijuana River Valley region.
   2. At least one in the Salton Sea region.
   3. At least one selected in consultation with a community that has experienced significant H₂S exposure.

COMMENTS

Hydrogen sulfide is a colorless, flammable, poisonous gas with a rotten egg odor. It burns in air with a pale blue flame. Hydrogen sulfide is emitted during the burning of sulfur-containing fuel oil and coal and wherever organic matter undergoes putrefaction. It is also emitted from a variety of industrial sources, including paper plants, leather tanning, production of heavy water for nuclear reactors, and manufacture of chemicals and metals. The primary stationary sources that have reported emissions of hydrogen sulfide in California are electrical service companies, oil and gas extraction operations, and steam and air conditioning supply services. Hydrogen sulfide also occurs in coal pits, volcanic gases, natural gas wells, sulfur springs, and in decaying organic matter containing sulfur. Hydrogen sulfide is known to cause negative respiratory and neurological impacts at the acute exposure level, and while epidemiological information for chronic effects is limited, some studies suggest chronic exposure levels may be associated with ocular, cardiovascular, respiratory, and neurological impacts. Hydrogen sulfide is regulated as a nuisance based on odor detection, with an air quality standard of 30 parts per billion (ppb) averaged over one hour. OEHHA adopted this standard as the acute reference exposure level and established a chronic inhalation reference exposure level of 8 ppb (prolonged exposure greater than one year).

Unlike the emissions from entities that ARB and local air districts regulate, there have been incidents of air emissions across the state that do not have a clear responsible party, but may far exceed established standards and have significant impacts on neighboring communities. The two situations highlighted by this bill are examples of these "orphan incidents."

Near the California-Mexico border, raw sewage from Tijuana crosses into San Diego County polluting the Tijuana River Valley with industrial chemicals, pesticides, and trash. As this transboundary pollution meanders through the valley, it generates hydrogen sulfide emissions and local scientists and communities have raised alarms about a particular emission site on Saturn Blvd, infamously known as the "hot spot." A constricted culvert under Saturn Blvd accelerates the untreated wastewater, generating turbulence and emitting hydrogen sulfide. When the wastewater is not diverted in Mexico, hydrogen sulfide has been detected at 2100 ppb (1-hour average), which is 70 times the nuisance standard, and frequently spikes depending on the flow rate of the sewage. Local scientists have demonstrated that averaging the hydrogen sulfide data over 1 hour to compare to the 30 ppb standard does not capture exceedances that occur within minutes and are suspected to have negative public health implications. The community has called for standards that consider different averaging times to capture these spikes and subsequent public notice and response.

Located in Riverside and Imperial counties, the Salton Sea tends to be a major source of hydrogen sulfide emissions due to a large influx of nutrients through agricultural runoff and the declining water levels, which increase the sea's ability to mix. With summer conditions, monitoring efforts have shown that hydrogen sulfide frequently exceeds the 30 ppb standard, for hundreds of hours over the course of the season. The humid climate of the region anecdotally exacerbates health effects and the current standard does not take humidity into account. These emissions impact communities already overburdened and suffering respiratory impacts from other emissions originating from the progressively declining Salton Sea, such as aerosolized seawater containing toxins and particulate matter released from the exposed seabed.

According to the Author

SB 58 advances equity by improving the state's understanding of hydrogen sulfide exposure in disproportionately burdened communities, including the Tijuana River Valley and Salton Sea regions. These communities, often low-income, immigrant, Latino, and Tribal, experience repeated or prolonged exposure alongside other environmental and health stressors.

SB 58 requires a more comprehensive evaluation of hydrogen sulfide exposure, including acute and chronic impacts and vulnerable populations, to improve identification of gaps and inform sate responses. It seeks to strengthen understanding of community-level health risks and improve coordination among agencies responding to hydrogen sulfide events in the Tijuana River Valley and Salton Sea.

The bill seeks to improve the state's capacity to address environmental health disparities affecting vulnerable communities.

Arguments in Support

According to the County of San Diego, SB 58's intent to update hydrogen sulfide standards and develop health-based thresholds is critical to closing a decades-long regulatory gap and protecting vulnerable populations.

Arguments in Opposition

None received for current version.

FISCAL COMMENTS

According to the Assembly Appropriations Committee:

1. ARB estimates costs of $1.8 million in fiscal year (FY) 2027-28 for about six new positions, contract dollars, and equipment, followed by ongoing annual costs of $1.3 million in FY 2028-29 and ongoing (Air Pollution Control Fund).

Specifically, ARB expects to serve as a subject matter expert on H₂S emission sources, health effects from ambient exposures, cross-media releases, exposure mitigation strategies, health-based Reference Exposure Levels (RELs), and health- and nuisance-based standards; draft the required framework and manage subsequent updates; consult and coordinate with a diverse group of stakeholders; lead public workshops and engage in targeted outreach to affected communities; develop region-specific and multilingual educational resources on the response framework in coordination with community-based organizations; serve as the technical lead on developing monitoring plans; serve as the response and outreach lead for incident operations; provide technical support and deliver guidance and training to local air districts and health agencies on monitoring and response planning; and various other tasks.

As part of the costs outlined above, ARB anticipates needing portable field instruments as well as air monitoring equipment to respond to planned and unplanned releases, spikes in air quality, and emergency incidents.

1. The Office of Environmental Health Hazard Assessment (OEHHA) estimates ongoing annual costs of approximately $423,000 for two positions, a one-time contracting cost of $400,000, and ongoing annual contracting costs of $150,000 (General Fund). While the bill directs ARB to develop a response framework to address sources of H₂S, in practice, ARB is very likely to consult with OEHHA in developing the required framework. OEHHA has previously developed RELs for H₂S, which are used by ARB, local air districts, and others when evaluating emissions from facilities, permitting, and conducting health risk assessments. Accordingly, OEHHA expects to lend its technical expertise to ARB in the development and updating of H₂S thresholds, participate in the required public workshops, and rely on a contractor for some of its technical support needs.
2. the Office of Emergency Services (OES) and the State Department of Public Health (CDPH) anticipate minor and absorbable costs to consult with ARB.
3. Costs of an unknown, likely absorbable, amount for the regional water quality control boards to consult with ARB.

VOTES

SENATE FLOOR: 39-0-1

YES: Allen, Alvarado-Gil, Archuleta, Arreguín, Ashby, Becker, Blakespear, Cabaldon, Caballero, Cervantes, Choi, Cortese, Dahle, Durazo, Grayson, Grove, Hurtado, Jones, Laird, Limón, McGuire, McNerney, Menjivar, Niello, Ochoa Bogh, Padilla, Pérez, Reyes, Richardson, Rubio, Seyarto, Smallwood-Cuevas, Stern, Strickland, Umberg, Valladares, Wahab, Weber Pierson, Wiener

ABS, ABST OR NV: Gonzalez

ASM NATURAL RESOURCES: 14-0-0

YES: Bryan, Ellis, Alanis, Connolly, Garcia, Haney, Hoover, Kalra, Macedo, Muratsuchi, Pellerin, Schultz, Wicks, Zbur

ASM APPROPRIATIONS: 11-0-4

YES: Wicks, Arambula, Calderon, Caloza, Fong, Mark González, Krell, Pacheco, Pellerin, Sharp-Collins, Solache

ABS, ABST OR NV: Hoover, Dixon, Ta, Tangipa

UPDATED

VERSION: August 13, 2026

CONSULTANT: Lawrence Lingbloom / NAT. RES. / (916) 319-2092 FN: 0003612

Date of Hearing: August 5, 2026

ASSEMBLY COMMITTEE ON APPROPRIATIONS

Buffy Wicks, Chair

SBPCA Bill Id:SB 58

Author:(Padilla) – As Amended Ver:June 15, 2026

Urgency: No State Mandated Local Program: No Reimbursable: No

SUMMARY:

This bill requires the Air Resources Board (ARB) to develop a response framework to address fugitive and natural sources of hydrogen sulfide (H₂S).

Specifically, this bill, among other things:

1. Requires ARB, in consultation with local air districts, the Office of Emergency Services (OES), the State Department of Public Health (CDPH), regional water quality control boards or other local or regional authorities, local environmental and public health agencies, universities and academic institutions, affected tribal governments, and community-based organizations, to develop a response framework that establishes best practices and guidance for addressing fugitive and natural sources of H₂S gas and for community preparation and response to H₂S exposure events originating from these sources, as specified.
2. Requires ARB, among other things, to conduct at least three public workshops, with at least one located in the Tijuana River Valley region, at least one in the Salton Sea region, and at least one selected in consultation with a community that has experienced significant H₂S exposure.

FISCAL EFFECT:

1) ARB estimates costs of $1.8 million in fiscal year (FY) 2027-28 for about six new positions, contract dollars, and equipment, followed by ongoing annual costs of $1.3 million in FY 2028-29 and ongoing (Air Pollution Control Fund).

Specifically, ARB expects to serve as a subject matter expert on H₂S emission sources, health effects from ambient exposures, cross-media releases, exposure mitigation strategies, health-based Reference Exposure Levels (RELs), and health- and nuisance-based standards; draft the required framework and manage subsequent updates; consult and coordinate with a diverse group of stakeholders; lead public workshops and engage in targeted outreach to affected communities; develop region-specific and multilingual educational resources on the response framework in coordination with community-based organizations; serve as the technical lead on developing monitoring plans; serve as the response and outreach lead for incident operations; provide technical support and deliver guidance and training to local air districts and health agencies on monitoring and response planning; and various other tasks.

As part of the costs outlined above, ARB anticipates needing portable field instruments as well as air monitoring equipment to respond to planned and unplanned releases, spikes in air quality, and emergency incidents.

2) The Office of Environmental Health Hazard Assessment (OEHHA) estimates ongoing annual costs of approximately $423,000 for two positions, a one-time contracting cost of $400,000, and ongoing annual contracting costs of $150,000 (General Fund). While the bill directs ARB to develop a response framework to address sources of H₂S, in practice, ARB is very likely to consult with OEHHA in developing the required framework. OEHHA has previously developed RELs for H₂S, which are used by ARB, local air districts, and others when evaluating emissions from facilities, permitting, and conducting health risk assessments. Accordingly, OEHHA expects to lend its technical expertise to ARB in the development and updating of H₂S thresholds, participate in the required public workshops, and rely on a contractor for some of its technical support needs.

1. OES and CDPH anticipate minor and absorbable costs to consult with ARB.
2. Costs of an unknown, likely absorbable, amount for the regional water quality control boards to consult with ARB.

COMMENTS:

1) Purpose. According to the author:

SB 58 advances equity by improving the state’s understanding of hydrogen sulfide exposure in disproportionately burdened communities, including the Tijuana River Valley and Salton Sea regions. These communities, often low-income, immigrant, Latino, and Tribal, experience repeated or prolonged exposure alongside other environmental and health stressors.

2) Background. H₂S, commonly associated with sewage, landfills, geothermal fields, and oil and natural gas extraction, is a toxic gas that produces a foul odor. H₂S is known to cause negative respiratory and neurological impacts at the acute exposure level. While epidemiological information for chronic effects is limited, some studies suggest chronic exposure levels may be associated with ocular, cardiovascular, respiratory, and neurological impacts. ARB regulates H₂S as a nuisance odor with the state standard established at 30 parts per billion averaged over one hour. ARB adopted this standard in 1969 and has not updated it since. Unlike the emissions from entities that ARB and local air districts regulate, there have been incidents of air emissions across the state that do not have a clear responsible party but may far exceed established standards and significantly harm neighboring communities.

Among others in support of this bill, San Diego County writes that the Tijuana River Valley faces an ongoing environmental and public health crisis driven by decades of transboundary sewage flows, which disproportionately affect already overburdened communities. This includes increased H₂S exposure, which is often linked to sewage decomposition and anaerobic activity in impacted areas like the Tijuana River Valley. The county writes, “SB 58’s intent to update [H₂S] standards and develop health-based thresholds is critical to closing a decades-long regulatory gap and protecting vulnerable populations.”

Similarly, the Tijuana River Coalition writes that overburdened communities surrounding the Salton Sea experience frequent elevated and chronic low-level H₂S concentrations, caused by anaerobic biological activity, decomposition of organic matter, and shoreline emissions, with recorded levels frequently exceeding the state standard. The coalition argues, “Currently, no uniform standard on [H₂S] exists across state and federal agencies. By conducting a review, we can fully understand the risk posed to human health and ensure we are taking appropriate steps to protect Californians.”

There is no opposition registered against this bill.

Analysis Prepared by: Nikita Koraddi / APPR. / (916) 319-2081

Date of Hearing: June 22, 2026

ASSEMBLY COMMITTEE ON NATURAL RESOURCES

Isaac G. Bryan, Chair

SBPCA Bill Id:SB 58

Author:(Padilla) – As Amended Ver:June 15, 2026

SENATE VOTE: 39-0

SUBJECT: Air quality: standard: hydrogen sulfide

SUMMARY: Requires the Air Resources Board (ARB) to develop a response framework to address fugitive and natural sources of hydrogen sulfide (H₂S).

EXISTING LAW:

1. The federal Clean Air Act (CAA) and its implementing regulations set National Ambient Air Quality Standard (NAAQS) for six criteria pollutants, designate air basins that do not achieve NAAQS as nonattainment, and require states with nonattainment areas to submit a State Implementation Plan (SIP) detailing how they will achieve compliance with NAAQS. (42 U.S.C. 7401 et seq.)
2. Provides the ARB with primary responsibility for control of mobile source air pollution and provides that local air districts have primary responsibility for controlling air pollution from all sources, other than emissions from mobile sources, and establishes certain powers, duties, and requirements for those districts. (Health and Safety Code (HSC) 39500 et seq. and 40000 et seq.)
3. Requires, subject to the powers and duties of the ARB, air districts to adopt and enforce rules and regulations to achieve and maintain the state and federal air quality standards in all areas affected by emission sources under their jurisdiction, and to enforce all applicable provisions of state and federal law. (HSC 40001)
4. Prohibits any person from discharging from any source quantities of air contaminants or other material that cause injury, detriment, nuisance, or annoyance to any considerable number of persons or to the public, or that endanger the comfort, repose, health, or safety of any of those persons or the public. (HSC 41700)
5. Establishes the Air Toxics “Hot Spots” Information and Assessment Act of 1987 to, among other things, require a health risk assessment to be submitted to the air districts that evaluates and predicts the dispersion of hazardous substances in the environment and the potential for exposure of human populations, and to assess and quantify both the individual and population wide health risks associated with those levels of exposure. (HSC 44300 et seq.)
6. Requires the Office of Environmental Health Hazard Assessment (OEHHA) to adopt health-based exposure standards, known as Reference Exposure Levels (RELs), for toxic air contaminants, including H₂S. (HSC 44360)

THIS BILL:

1. Requires ARB, in consultation with the local air districts, the Office of Emergency Services, the State Department of Public Health, regional water quality control boards or other local or regional authorities, local environmental and public health agencies, universities and academic institutions, affected tribal governments, and community-based organizations, to develop a response framework that establishes best practices and guidance for addressing fugitive and natural sources of H₂S gas and for community preparation and response to H₂S exposure events originating from these sources.
2. Requires ARB to consider cross-media releases, and develop integrated, multiagency approaches to identify and address fugitive and natural sources, and methods for reducing identified fugitive and natural sources of H₂S gas in impacted communities.
3. Requires ARB to consider and evaluate the inadequacies of the Acute, 8-hour, and Chronic Reference Exposure Levels for fugitive and natural sources of emissions for developing the response plan. Requires the evaluation to consider the following:
   1. Current scientific literature regarding acute, subchronic, and chronic health effects of H₂S exposure, including the impact of chronic low-level exposure.
   2. The adequacy of current averaging times for characterizing hazardous exposure, including the frequency and duration of possible exposures.
   3. The influence of local and regional climates, outdoor, and indoor settings on exposure.
4. Requires ARB to conduct at least three public workshops located in the following:
   1. At least one in the Tijuana River Valley region.
   2. At least one in the Salton Sea region.
   3. At least one selected in consultation with a community that has experienced significant H₂S exposure.
5. Establishes the following definitions:
   1. “Fugitive source” means any source of emissions of H₂S gas that is not currently regulated as a stationary source by a local air district.
   2. “Local environmental and public health agencies” means any local entity that a health officer serves, or any local environmental health agency.
   3. “Natural source” means a source of H₂S occurring in nature as a result of environmental circumstances.

FISCAL EFFECT: Unknown

COMMENTS:

1. Background. Hydrogen sulfide is a colorless, flammable, poisonous gas with a rotten egg odor. It burns in air with a pale blue flame. Hydrogen sulfide is emitted during the burning of sulfur-containing fuel oil and coal and wherever organic matter undergoes putrefaction. It is also emitted from a variety of industrial sources, including paper plants, leather tanning, production of heavy water for nuclear reactors, and manufacture of chemicals and metals. The primary stationary sources that have reported emissions of hydrogen sulfide in California are electrical service companies, oil and gas extraction operations, and steam and air conditioning supply services. Hydrogen sulfide also occurs in coal pits, volcanic gases, natural gas wells, sulfur springs, and in decaying organic matter containing sulfur. Hydrogen sulfide is known to cause negative respiratory and neurological impacts at the acute exposure level, and while epidemiological information for chronic effects is limited, some studies suggest chronic exposure levels may be associated with ocular, cardiovascular, respiratory, and neurological impacts. Hydrogen sulfide is regulated as a nuisance based on odor detection, with an air quality standard of 30 parts per billion (ppb) averaged over one hour. OEHHA adopted this standard as the acute reference exposure level and established a chronic inhalation reference exposure level of 8 ppb (prolonged exposure greater than one year).

Unlike the emissions from entities that ARB and local air districts regulate, there have been incidents of air emissions across the state that do not have a clear responsible party, but may far exceed established standards and have significant impacts on neighboring communities. The two situations highlighted by this bill are examples of these “orphan incidents.”

Near the California-Mexico border, raw sewage from Tijuana crosses into San Diego County polluting the Tijuana River Valley with industrial chemicals, pesticides, and trash. As this transboundary pollution meanders through the valley, it generates hydrogen sulfide emissions and local scientists and communities have raised alarms about a particular emission site on Saturn Blvd, infamously known as the “hot spot.” A constricted culvert under Saturn Blvd accelerates the untreated wastewater, generating turbulence and emitting hydrogen sulfide. When the wastewater is not diverted in Mexico, hydrogen sulfide has been detected at 2100 ppb (1-hour average), which is 70 times the nuisance standard, and frequently spikes depending on the flow rate of the sewage. Local scientists have demonstrated that averaging the hydrogen sulfide data over 1 hour to compare to the 30 ppb standard does not capture exceedances that occur within minutes and are suspected to have negative public health implications. The community has called for standards that consider different averaging times to capture these spikes and subsequent public notice and response.

Located in Riverside and Imperial counties, the Salton Sea tends to be a major source of hydrogen sulfide emissions due to a large influx of nutrients through agricultural runoff and the declining water levels, which increase the sea’s ability to mix. With summer conditions, monitoring efforts have shown that hydrogen sulfide frequently exceeds the 30 ppb standard, for hundreds of hours over the course of the season. The humid climate of the region anecdotally exacerbates health effects and the current standard does not take humidity into account. These emissions impact communities already overburdened and suffering respiratory impacts from other emissions originating from the progressively declining Salton Sea, such as aerosolized seawater containing toxins and particulate matter released from the exposed seabed.

1. Author’s statement:

SB 58 advances equity by improving the state’s understanding of hydrogen sulfide exposure in disproportionately burdened communities, including the Tijuana River Valley and Salton Sea regions. These communities, often low-income, immigrant, Latino, and Tribal, experience repeated or prolonged exposure alongside other environmental and health stressors.

SB58 requires a more comprehensive evaluation of hydrogen sulfide exposure, including acute and chronic impacts and vulnerable populations, to improve identification of gaps and inform sate responses. It seeks to strengthen understanding of community-level health risks and improve coordination among agencies responding to hydrogen sulfide events in the Tijuana River Valley and Salton Sea.

The bill seeks to improve the state’s capacity to address environmental health disparities affecting vulnerable communities.

REGISTERED SUPPORT / OPPOSITION:

Support

A Voice for Choice Advocacy
Climate Reality Project San Fernando Valley Chapter
Climate Reality Project, Los Angeles Chapter
County of San Diego

League of Women Voters of California
Sierra Club

Opposition

California Manufacturers and Technology Association

Analysis Prepared by: Lawrence Lingbloom / NAT. RES. /

 THIRD READING  

Bill No: SB 58

Author: Padilla (D), et al.

Amended: 1/14/26

Vote: 21

SENATE ENVIRONMENTAL QUALITY COMMITTEE: 7-0, 1/13/26

AYES: Blakespear, Valladares, Dahle, Gonzalez, Menjivar, Pérez, Reyes

NO VOTE RECORDED: Hurtado

SENATE APPROPRIATIONS COMMITTEE: 7-0, 1/22/26

AYES: Caballero, Seyarto, Cabaldon, Dahle, Grayson, Richardson, Wahab

SUBJECT: Air quality: standard: hydrogen sulfide

SOURCE: Author

DIGEST:

This bill requires the Office of Environmental Health Hazard Assessment (OEHHA) to develop additional health-based threshold levels for hydrogen sulfide.

ANALYSIS:

Existing federal law:

1. The federal Clean Air Act (CAA) and its implementing regulations set National Ambient Air Quality Standard (NAAQS) for six criteria pollutants, designate air basins that do not achieve NAAQS as nonattainment, and require states with nonattainment areas to submit a State Implementation Plan (SIP) detailing how they will achieve compliance with NAAQS. (42 U.S.C. 7401 et seq.)

Existing state law:

1. Establishes OEHHA under the California Environmental Protection Agency and authorizes OEHHA to perform activities relating to the assessment of human health risks of chemicals, toxicology, or scientific consultation. (HSC § 59000 et. seq.)
2. Establishes the California Air Resources Board (CARB) as the air pollution control agency in California and requires CARB, among other things, to control emissions from a wide array of mobile sources and coordinate with local air districts to control emissions from stationary sources in order to implement the CAA. (Health and Safety Code (HSC) § 39000 et seq.)
3. Requires CARB to adopt ambient air quality standards for each air basin in consideration of the public health, safety, and welfare, and based upon the recommendations of OEHHA. (HSC § 39606(a)(2))
4. Authorizes CARB or local air districts to adopt regulations to control pollutants associated with state ambient air quality standards, including hydrogen sulfide. (HSC § 40926)
5. Required CARB, in consultation with OEHHA, to review all existing health-based ambient air quality standards, including hydrogen sulfide, to determine whether they adequately protect the health of the public, including infants and children, before December 31, 2000. (HSC § 39606(d))
6. Requires, subject to the powers and duties of CARB, local air districts to adopt and enforce rules and regulations to achieve and maintain the state and federal air quality standards in all areas affected by emission sources under their jurisdiction, and to enforce all applicable provisions of state and federal law. (HSC § 40001)
7. Authorizes local air district rules and regulations to provide for the prevention and abatement of air pollution episodes which cause discomfort or health risks to a significant number of persons. (HSC § 40001(b))
8. Authorizes local air districts to sponsor, coordinate, and promote projects that will lead to the prevention, mitigation, or cure of the adverse effects of air pollution, including the adverse health effects of air pollution. (HSC § 40004)

This bill:

1. Requires OEHHA to develop health-based threshold levels for hydrogen sulfide, in addition to any standards adopted by CARB, on or before January 1, 2030.
2. Requires OEHHA, in developing the threshold levels, to consider all of the following:
   1. Current scientific literature regarding acute, subchronic, and chronic health effects of hydrogen sulfide exposure;
   2. The adequacy of current averaging times and the need for additional threshold levels based on various averaging times;
   3. Outdoor and indoor air exposure;
   4. Local and regional climates, including whether existing standards and levels are appropriate for specific locations;
   5. Current federal, state, and international exposure guidelines; and,
   6. Corresponding actions for threshold levels.
3. Authorizes OEHHA to develop threshold levels for additional air pollutants upon an appropriation from the Legislature.
4. Authorizes OEHHA to develop threshold levels in consultation with CARB, air districts, the California Department of Public Health (CDPH), local or regional authorities, local environmental and public health agencies, universities and academic institutions, affected tribal governments, and community-based organizations.
5. Requires OEHHA to conduct at least three public workshops, with at least one in the Tijuana River Valley region, the Salton Sea region, and a location selected in consultation with a community that has experienced significant hydrogen sulfide exposure.
6. Requires air districts to adopt, and authorizes local environmental and public health agencies to consider, any threshold level developed by OEHHA.
7. Authorizes CARB to adopt additional or updated standards based on the threshold levels developed by OEHHA.
8. States the intent of the Legislature to develop guidelines that would require CARB, in consultation with specified entities, to develop a response framework based on the threshold levels developed by OEHHA.
9. Makes related findings and declarations.

Background

1. Hydrogen sulfide. Hydrogen sulfide, commonly associated with sewage, landfills, geothermal fields, and oil and natural gas extraction, is a toxic gas that produces a foul odor. Hydrogen sulfide is known to cause negative respiratory and neurological impacts at the acute exposure level, and while epidemiological information for chronic effects is limited, some studies suggest chronic exposure levels may be associated with ocular, cardiovascular, respiratory, and neurological impacts.^{[1],[2],[3],[4]}
2. Standards vs. thresholds. As amended January 5, 2026, this bill required CARB to adopt an updated standard for hydrogen sulfide. The role of CARB and local air districts is to protect the public from the harmful effects of air pollution and drive reductions through various programs and actions. The ambient air quality standards serve as a metric through which CARB and local air districts drive reductions in pollutants and coordinate efforts to maintain them. If an air quality standard is not met in a certain area, then CARB and local air districts must develop a plan to attain that standard. CARB and local air districts regulate mobile and stationary sources of pollution, respectively. These sources typically have a responsible party who can respond to regulatory requirements as outlined in attainment plans, face penalties for non-compliance, and implement controls to abate their emissions

Threshold levels, on the other hand, can be used as a tool for various programs and response mechanisms to protect public health, regardless of source. OEHHA typically establishes reference exposure levels (REL) to assess the risk of exposure to various toxins.^[5] RELs are used in the Air Toxics Hot Spots Program to assess the risk of emissions by stationary sources and for health risk assessments. OEHHA has also been tasked to develop other thresholds, like for heavy metals released by metal shredding facilities (AB 2851, Bonta, Chapter 743, Statutes of 2024). In this case, the threshold levels will serve as triggers for community notification and potentially other actions.

This bill was amended in the Senate Environmental Quality Committee to require OEHHA to develop threshold levels for hydrogen sulfide in addition to existing RELs, rather than requiring CARB to update the hydrogen sulfide standard. Currently, CARB regulates hydrogen sulfide as a nuisance odor with the state standard established at 30 parts per billion (ppb) averaged over one hour.^[6] OEHHA adopted this standard as the acute REL and established a chronic inhalation REL of 8 ppb (prolonged exposure greater than one year).¹

1. The odd ones out. Unlike the emissions from entities that CARB and local air districts regulate, there have been incidents of air emissions across the state that do not have a clear responsible party, but may far exceed established standards and have significant impacts on neighboring communities. The two situations highlighted by this bill are examples of these “orphan incidents”:
   1. Tijuana River Valley. Near the California-Mexico border, raw sewage from Tijuana crosses into San Diego County polluting the Tijuana River Valley with industrial chemicals, pesticides, and trash.^[7],[8] As this transboundary pollution meanders through the valley, it generates hydrogen sulfide emissions and local scientists and communities have raised alarms about a particular emission site on Saturn Blvd, infamously known as the “hot spot”.^[9] A constricted culvert under Saturn Blvd accelerates the untreated wastewater, generating turbulence and emitting hydrogen sulfide. When the wastewater is not diverted in Mexico, hydrogen sulfide has been detected at 2100 ppb (1-hour average), which is 70 times the nuisance standard, and frequently spikes depending on the flow rate of the sewage. Local scientists have demonstrated that averaging the hydrogen sulfide data over 1 hour to compare to the 30 ppb standard does not capture exceedances that occur within minutes and are suspected to have negative public health implications. The community has called for standards that consider different averaging times to capture these spikes and subsequent public notice and response.
   2. Salton Sea. Located in Riverside and Imperial counties, the Salton Sea tends to be a major source of hydrogen sulfide emissions due to a large influx of nutrients through agricultural runoff and the declining water levels, which increase the sea’s ability to mix.^{[10],[11],[12],[13]} With summer conditions, monitoring efforts have shown that hydrogen sulfide frequently exceeds the 30 ppb standard, for hundreds of hours over the course of the season.^[14] The humid climate of the region anecdotally exacerbates health effects and the current standard does not take humidity into account. These emissions impact communities already overburdened and suffering respiratory impacts from other emissions originating from the progressively declining Salton Sea, such as aerosolized seawater containing toxins and particulate matter released from the exposed seabed.¹¹

Differences between monitoring techniques and deployment locations between local agencies and external groups have highlighted discrepancies in exceedances of the hydrogen sulfide standard.¹⁴ While there are jurisdictional limitations and particular considerations that influence where air quality management districts deploy their monitors, universities and non-governmental organizations have called for more comprehensive monitoring that factors in wind direction.^11,14,[15]

These incidents fall outside existing regulatory frameworks because attainment plans, and any subsequent action, may not be applicable to sources without specific and identifiable responsible parties. Thus standards, used to achieve attainment, may not be the most useful tool in addressing the harms of these incidents.

1. Responses involving responsible parties. There have been other incidents of hydrogen sulfide releases in which local agencies were able to identify a responsible party, and their responses have varied. Some of the actions taken in these situations may benefit communities impacted by such “orphan incidents”. For instance, a warehouse fire led to the release of product chemicals in the Dominguez Channel in Los Angeles County, prompting biological processes that resulted in hydrogen sulfide emissions. Technology played a key role in the resolution of this emergency, as a variety of monitoring technologies were deployed such as handheld, mobile, and fixed monitors, and odor neutralizers and aeration devices were used to mitigate emissions.^[16] In 2015, a gas blowout occurred at the Aliso Canyon natural gas storage facility in LA County that led to the release of hydrogen sulfide emissions.^[17] In part, the South Coast Air Quality Management District and CARB responded by establishing criteria for typical air quality levels for hydrogen sulfide at 10 ppb and reporting levels at 5 ppb.^[18],[19]

Comments

1. Purpose of Bill. According to the author, “For generations, families in some of the most economically strained parts of the state have suffered from millions of gallons of sewage and pollution flowing through the Tijuana River and emissions from the Salton Sea. This pollution has been harming our community for decades and yet our air quality standards haven’t been updated in nearly half a century. It is unacceptable that the regulatory standard monitoring the very air our families breathe is so woefully out of date, leaving communities at risk. Making this critical change is a long overdue step towards addressing an issue that has been allowed to fester for decades. It is critical that Sacramento finally act to help our community.”
2. Response thresholds and a new framework. Whether there is an identified responsible party or not, exceedances of the hydrogen sulfide standard tend to generate varied responses from local communities and agencies. Each response is likely tailored to the particular public health impacts and local needs demonstrated by each community, but not all responses would work for all situations. It is also clear that the current standard for hydrogen sulfide may be insufficient in indicating hazards to public health. Thus, a new regulatory framework with tailored metrics or trigger points that center public health and response may better meet the needs of impacted communities.

Advisory and response thresholds developed by OEHHA could serve as metrics or trigger points and could consider different averaging times, climates and new research. Several countries have short-term 30-minute standards and long-term 24-hour standards for hydrogen sulfide.^[20] It is also not clear the extent to which air districts and local agencies consider Acute Exposure Guideline Levels (AEGLs), which are typically used by emergency responders during accidental chemical releases.^[21] AEGLs for hydrogen sulfide have been established at intervals under an hour, and given that emissions data may be solely averaged to compare to the 1-hour standard, this metric may be underutilized. Newly developed thresholds could consider these metrics or develop additional metrics.

Given that “orphan incidents” can lack a designated regulatory framework, discretion is left to local agencies on how to respond. It can be unclear what the most appropriate response would be, especially since local agencies may lack experience with such incidents and they could vary with context. A review of best practices during similar incidents inside and outside the state could inform guidelines on public notification procedures, local agency response actions and coordination, mitigation technologies, public health assessments, monitoring strategies, data collection, reporting, and resource availability. Establishing guidance could support local air districts and public health agencies and pairing this guidance with newly established response thresholds and existing standards could bring clarity in challenging situations.

FISCAL EFFECT: Appropriation: No Fiscal Com.: Yes Local: Yes

SUPPORT: (Verified 1/23/26)

Alianza Coachella Valley

Alliance San Diego

Azul

Cactustocloud Institute

City of Imperial

City of Imperial Beach

City of Indian Wells

City of Indio

City of Needles

Coachella Valley Association of Governments

Coalition for Clean Air

Coronado Democratic Club

Desert Care Network

Desert Recreation District

Environmental Health Coalition

Imperial Valley Equity & Justice Coalition

Imperial Valley Healthcare District

LA Cooperativa Campesina De California

Latino Outdoors

Leadership Counsel for Justice and Accountability

Loma Linda University Adventist Health Sciences Center and its Affiliated Entities

Los Amigos De LA Comunidad, INC.

Outdoor Outreach

Palm Desert Area Chamber of Commerce

San Diego for Every Child

Sierra Club

Sierra Service Project

Solana Beach Eco Rotary Club

Surfrider Foundation

The Border Group

Tijuana River Coaliton

Un Mar De Colores

Wildcoast

YMCA of San Diego County

OPPOSITION: (Verified 1/23/26)

None received

Prepared by: Taylor McKie / E.Q. / (916) 651-4108

1/23/26 15:39:08

**** END ****

1. Office of Environmental Health and Hazard Assessment. (2000). Chronic Toxicity Summary: Hydrogen Sulfide. ↑

2. Office of Environmental Health and Hazard Assessment. (2008). Acute Toxicity Summary: Hydrogen Sulfide. ↑

3. Batterman, S., et. al. (2023). Low level exposure to hydrogen sulfide: a review of emissions, community exposure, health effects, and exposure guidelines. ↑

4. Nuvolone, D., et. al. (2019). Health effects associated with chronic exposure to low-level hydrogen sulfide from geothermoelectric power plants. ↑

5. Office of Environmental Health and Hazard Assessment. (2023). OEHHA Acute, 8-hour and Chronic Reference Exposure Level (REL) Summary. ↑

6. California Air Resources Board. (2026). Hydrogen Sulfide & Health. ↑

7. McLamb, F., et. al. (2024). Evidence of transboundary movement of chemicals from Mexico to the U.S. in Tijuana River Estuary sediments. ↑

8. Cooper, A., et. al. (2025). Identifying wastewater chemicals in coastal aerosols. ↑

9. Rico, B., et. al. (2025). Heavily polluted Tijuana River drives regional air quality crisis. ↑

10. Reese, B., et. al. (2008). Hydrogen sulfide production and volatilization in a polymictic eutrophic saline lake, Salton Sea, California. ↑

11. Centeno, D., et. al. (2025). Hypereutrophication, Hydrogen Sulfide, and Environmental Injustices: Mechanisms and Knowledge Gaps at the Salton Sea. ↑

12. Márquez, C., et. al. (2025). Inadequate Government-Led Water-Quality Monitoring Hinders Improvement Efforts in the Salton Sea. ↑

13. Wilson, J. (2024). This stinks: Salton Sea now emitting bad smells year round. Here’s why. ↑

14. Márquez, C., et. al. (2025). Salton Sea Exceedances of California’s Air Quality Standards Highlight Governance Gaps and Monitoring Needs. ↑

15. Wilson, J. (2025). Study: Salton Sea is emitting foul gas at levels worse than official monitors show. ↑

16. South Coast Air Quality Management District. (2024). Dominguez Channel Odor Event. ↑

17. County of Los Angeles Public Health. (n.d.). Aliso Canyon Disaster Health Research Study: Blowout and Public Health Disaster. ↑

18. South Coast Air Quality Management District. (2016). Aliso Canyon Facility Monitoring Network Plan. ↑

19. South Coast Air Quality Management District and California Air Resources Board. (2016). Criteria for Determining when Air Quality in the Porter Ranch and Surrounding Communities Has Returned to Typical Levels. ↑

20. Collins, J. and Lewis, D. (2000). Hydrogen Sulfide: Evaluation of Current California Air Quality Standards with Respect to Protection of Children. ↑

21. U.S. Environmental Protection Agency. (2025). Acute Exposure Guideline Levels for Airborne Chemicals. ↑

SENATE COMMITTEE ON

Senator Anna Caballero, Chair

2025 - 2026 Regular Session

SB 58 (Padilla) - Air quality: standard: hydrogen sulfide

Bill Summary:

This bill would require the Office of Environmental Health Hazard Assessment (OEHHA) to develop health-based threshold levels for hydrogen sulfide, among other things, and would require the air pollution control districts and air quality management districts to adopt, and would authorize local environmental and public health agencies to consider, any threshold level later developed by the office pursuant to the bill.

Fiscal Impact:

• OEHHA estimates ongoing annual costs of approximately $423,000 (General Fund) for two positions and one-time funding of $400,000 with $150,000 ongoing (General Fund) in contracting costs. The staff and $400,000 would support the technical development of thresholds for hydrogen sulfide, including the required public workshops, and consultation with the California Air Resources Board (CARB) on developing the response framework intended by the bill. The contract dollars would address technical support needs, including but not limited to work on health impacts of odors from hydrogen sulfide, and community engagement. OEHHA asserts that ongoing staff resources and the $150,000 ongoing in contract dollars would be needed to maintain and update the hydrogen sulfide levels as appropriate and to enable OEHHA to develop thresholds, under Health and Safety Code 41514.7(c)(2), for other chemicals.
• CARB estimates ongoing costs of about $1.1 million annually (Air Pollution Control Fund, General Fund, or other special fund) to consult with OEHHA and update or adopt hydrogen sulfide standards as recommended by OEHHA.

Background:

Hydrogen sulfide, commonly associated with sewage, landfills, geothermal fields, and oil and natural gas extraction, is a toxic gas that produces a foul odor. Hydrogen sulfide is known to cause negative respiratory and neurological impacts at the acute exposure level, and while epidemiological information for chronic effects is limited, some studies suggest chronic exposure levels may be associated with ocular, cardiovascular, respiratory, and neurological impacts.

Hydrogen sulfide is regulated by CARB as a nuisance based on odor detection and the CAAQS for the chemical has been established at 30 parts per billion (ppb) averaged over one hour. OEHHA adopted this standard as the acute reference exposure level and established a chronic inhalation reference exposure level of 8 ppb (prolonged exposure greater than one year).3 A health-based standard for hydrogen sulfide would be established at a much higher level, as severe adverse health impacts are expected to occur at concentrations higher than 30 ppb.

As research progresses and new findings emerge, the air quality standards adopted by agencies adapt. NAAQS are reviewed by the U.S. Environmental Protection Agency (U.S. EPA) at five-year intervals, and all have been updated within the last 15 years. For all CAAQS, the last review took place on December 2000 and was initiated by the Children’s Environmental Health Protection Act (SB 25, Escutia, Chapter 731, Statutes of 1999). While the review (2000 Standards Review) led to updates for some standards, it ultimately concluded that the standard for hydrogen sulfide was reasonably health protective. The report further stated that the ambient levels of hydrogen sulfide are very low throughout most the state and the standard was considered a low priority for review since it was meant “to prevent odor annoyance and associated symptoms, outcomes that are clearly not as serious as those associated with [other] pollutants”.

Proposed Law:

This bill would:

• require, on or before January 1, 2030, OEHHA to develop health-based threshold levels for hydrogen sulfide.
• Further authorize OEHHA to develop threshold levels for additional air pollutants with the considerations specified for hydrogen sulfide upon an appropriation for this purpose from the Legislature.
• Require OEHHA to conduct at least 3 public workshops, including at least one located in the Tijuana River Valley region, at least one located in the Salton Sea region, and at least one selected in consultation with a community that has experienced significant hydrogen sulfide exposure.
• Require the air pollution control districts and air quality management districts to adopt, and would authorize local environmental and public health agencies to consider, any threshold level later developed by OEHHA pursuant to the bill. By imposing new duties on air pollution control districts and air quality management districts, the bill would impose a state-mandated local program.
• Authorize the California Air Resources Board (CARB) to adopt additional or updated standards based on the threshold levels developed pursuant to the bill.
• Express the intent of the Legislature to develop guidelines that would require CARB, in consultation with specified entities, to develop a response framework to establish best practices and guidance based on OEHHA’s development of thresholds established pursuant to the bill.

Related Legislation:

AB 1003 (Calderon, Chapter 537, Statutes of 2025) required a plan developed by CDPH with guidelines for significant air quality events to be completed by June 2027, and include public outreach and distribution of the plan.

AB 2851 (Bonta, Chapter 743, Statutes of 2025) required air districts to develop requirements for fence-line air quality monitoring and threshold levels for airborne contaminants associated with metal shredding facilities in consultation with OEHHA.

SB 867 (Allen, Chapter 83, Statutes of 2024) enacted the Safe Drinking Water, Wildfire Prevention, Drought Preparedness, and Clean Air Bond Act of 2024 authorizing the issuance of bonds in the amount of $10 billion to finance projects including, but not limited to drought, flood, and water resilience, coastal resilience, park creation, outdoor access, and clean air programs.

AB 619 (Calderon, Chapter 412, Statutes of 2021) required CDPH to develop a plan with recommendations and guidelines for counties to use in the case of significant air quality events caused by wildfires or other sources.

AB 1597 (Alvarez, 2023) would have authorized funds made available to the California Environmental Protection Agency (CalEPA) for North American Development Bank for loans, grants, and expenditures to address water quality problems arising in the California-Mexico cross-border watersheds. This bill was held on the suspense file in this committee.

AB 2248 (Eduardo Garcia, 2022) would have made $100 million available from the General Fund to the State Water Board for grants and direct expenditures to address water quality problems arising in the California-Mexico cross-border rivers. This bill was vetoed by Governor Newsom.

SB 1301 (Hueso, Chapter 368, Statutes of 2020) required CalEPA and the California Natural Resources Agency to collaborate to create a Tijuana River Valley Watershed Action Plan to be reviewed and updated on a 3-year cycle.

SB 690 (Hueso, Chapter 381, Statutes of 2019) encouraged the State Coastal Conservancy to prioritize projects identified in feasibility studies conducted by the County of San Diego for the Tijuana River Valley when expending funds to address transboundary flows and pollution in the Tijuana River Valley.

AB 965 (Eduardo Garcia, Chapter 668, Statutes of 2015) established the New River Wate Quality, Public Health, and River Parkway Development Program to coordinate funding and implementation for environmental and health projects and purposes relating to the California-Mexico border region.

AB 1095 (Eduardo Garcia, Chapter 722, Statutes of 2015) required the California Natural Resource Agency to submit a list of shovel-ready restoration projects for the Salton Sea to the Legislature by March 2016.

SB 277 (Ducheny, Chapter 611, Statutes of 2003) enacted the Salton Sea Restoration Act that established a fund for various purposes relating to restoration of the Salton Sea.

SB 25 (Escutia, Chapter 731, Statutes of 1999) required CARB to review all existing health-based ambient air quality standards to determine whether they adequately protect the health of the public, including infants and children, and to revise the highest priority air quality standard determined to be inadequate by December 2002.

-- END --

SENATE COMMITTEE ON ENVIRONMENTAL QUALITY

Senator Blakespear, Chair

2025 - 2026 Regular

Bill No: SB 58

SUBJECT: Air quality: standard: hydrogen sulfide

DIGEST: This bill requires the California Air Resources Board (CARB) to review the ambient air quality standard for hydrogen sulfide and adopt an updated standard to protect public health.

ANALYSIS:

Existing federal law:

1. The federal Clean Air Act (CAA) and its implementing regulations set National Ambient Air Quality Standard (NAAQS) for six criteria pollutants, designate air basins that do not achieve NAAQS as nonattainment, and require states with nonattainment areas to submit a State Implementation Plan (SIP) detailing how they will achieve compliance with NAAQS. (42 U.S.C. 7401 et seq.)

Existing state law:

1. Establishes CARB as the air pollution control agency in California and requires CARB, among other things, to control emissions from a wide array of mobile sources and coordinate with local air districts to control emissions from stationary sources in order to implement the CAA. (Health and Safety Code (HSC) § 39000 et seq.)
2. Requires CARB to adopt ambient air quality standards for each air basin in consideration of the public health, safety, and welfare, and based upon the recommendations of the Office of Environmental Health Hazard Assessment (OEHHA). (HSC § 39606(a)(2))
3. Authorizes CARB or local air districts to adopt regulations to control pollutants associated with state ambient air quality standards, including hydrogen sulfide. (HSC § 40926)
4. Required CARB, in consultation with OEHHA, to review all existing health-based ambient air quality standards, including hydrogen sulfide, to determine whether they adequately protect the health of the public, including infants and children, before December 31, 2000. (HSC § 39606(d))
5. Requires, subject to the powers and duties of CARB, local air districts to adopt and enforce rules and regulations to achieve and maintain the state and federal air quality standards in all areas affected by emission sources under their jurisdiction, and to enforce all applicable provisions of state and federal law. (HSC § 40001)
6. Authorizes local air district rules and regulations to provide for the prevention and abatement of air pollution episodes which cause discomfort or health risks to a significant number of persons (HSC § 40001(b))
7. Authorizes local air districts to sponsor, coordinate, and promote projects that will lead to the prevention, mitigation, or cure of the adverse effects of air pollution, including the adverse health effects of air pollution (HSC § 40004)
8. Establishes OEHHA under the California Environmental Protection Agency and authorizes OEHHA to perform activities relating to the assessment of human health risks of chemicals, toxicology, or scientific consultation (HSC § 59000 et. seq.)

This bill:

1. Requires CARB to conduct a comprehensive review of the current ambient air quality standard for hydrogen sulfide and adopt an updated standard to protect public health.
2. Requires CARB, in conducting the comprehensive review, to evaluate at least all of the following:
   1. Current scientific literature regarding the health effects of hydrogen sulfide exposure;
   2. Current federal, state, and international health-based exposure guidelines;
   3. Documented exposure conditions in the Tijuana River Valley and Salton Sea regions;
   4. The adequacy of current averaging times for toxic exposure assessments; and,
   5. Cumulative and disproportionate impacts on environmental justice communities.
3. Requires CARB to conduct at least three public workshops during the review in regions including the Tijuana River Valley, Salton Sea, and an additional location selected in consultation with overburdened communities.
4. Requires CARB to consult with local air districts, OEHHA, the California Department of Public Health (CDPH), affected tribal governments, and community-based organizations.
5. Requires CARB to publish a report on its website following the completion of the review that includes scientific findings, exposure conditions, proposed revised standards, and monitoring strategies.
6. Requires CARB to adopt an updated hydrogen sulfide ambient air quality standard to protect sensitive populations and overburdened communities within 12 months of publishing the report.
   
7. Makes related findings and declarations.
   

Background

1. Ambient air quality standards. The role of CARB and local air districts is to protect the public from the harmful effects of air pollution and drive reductions through various programs and actions. The ambient air quality standards, which define the maximum amount of pollutants that can be present in outdoor air without harming public health, serve as a metric through which CARB and local air districts drive reductions in pollutants and coordinate efforts to maintain them. The federal Clean Air Act requires that all states attain the National Ambient Air Quality Standards (NAAQS), which consist of standards for particulate matter, carbon monoxide, lead, ozone, and nitrogen and sulfur oxides.^[1] California has established additional standards (CAAQS) for those and other pollutants, including hydrogen sulfide.^[2] If an air quality standard is not met in a certain area, then CARB and local air districts must develop a plan to attain that standard.
2. Hydrogen sulfide. Hydrogen sulfide, commonly associated with sewage, landfills, geothermal fields, and oil and natural gas extraction, is a toxic gas that produces a foul odor. Hydrogen sulfide is known to cause negative respiratory and neurological impacts at the acute exposure level, and while epidemiological information for chronic effects is limited, some studies suggest chronic exposure levels may be associated with ocular, cardiovascular, respiratory, and neurological impacts.^{[3],[4],[5],[6]}

Hydrogen sulfide is regulated by CARB as a nuisance based on odor detection and the CAAQS for the chemical has been established at 30 parts per billion (ppb) averaged over one hour.^[7] OEHHA adopted this standard as the acute reference exposure level and established a chronic inhalation reference exposure level of 8 ppb (prolonged exposure greater than one year).³ A health-based standard for hydrogen sulfide would be established at a much higher level, as severe adverse health impacts are expected to occur at concentrations higher than 30 ppb.

As research progresses and new findings emerge, the air quality standards adopted by agencies adapt. NAAQS are reviewed by the U.S. Environmental Protection Agency (U.S. EPA) at five-year intervals, and all have been updated within the last 15 years. For all CAAQS, the last review took place on December 2000 and was initiated by the Children’s Environmental Health Protection Act (SB 25, Escutia, Chapter 731, Statutes of 1999). While the review (2000 Standards Review) led to updates for some standards, it ultimately concluded that the standard for hydrogen sulfide was reasonably health protective. The report further stated that the ambient levels of hydrogen sulfide are very low throughout most the state and the standard was considered a low priority for review since it was meant “to prevent odor annoyance and associated symptoms, outcomes that are clearly not as serious as those associated with [other] pollutants”.^[8]

1. The odd ones out. While CARB’s regulatory framework focuses on mobile sources of emissions, like motor vehicles, the local air districts regulate stationary sources, such as industrial facilities. These sources typically have a responsible party who can respond to regulatory requirements, face penalties for non-compliance, and implement controls to abate their emissions. Unlike these regulated entities, there have been incidents or stationary sources of air emissions across the state that do not have a clear responsible party, but may far exceed established standards and have significant impacts on neighboring communities. The two situations highlighted by this bill are examples of these “orphan incidents”:
   1. Tijuana River Valley. Near the California-Mexico border, raw sewage from Tijuana crosses into San Diego County polluting the Tijuana River Valley with industrial chemicals, pesticides, and trash.^[9],[10] As this transboundary pollution meanders through the valley, it generates hydrogen sulfide emissions and local scientists and communities have raised alarms about a particular emission site on Saturn Blvd, infamously known as the “hot spot”.^[11] A constricted culvert under Saturn Blvd accelerates the untreated wastewater, generating turbulence and emitting hydrogen sulfide. When the wastewater is not diverted in Mexico, hydrogen sulfide has been detected at 2100 ppb (1-hour average), which is 70 times the nuisance standard, and frequently spikes depending on the flow rate of the sewage. Local scientists have demonstrated that averaging the hydrogen sulfide data over 1 hour to compare to the 30 ppb standard does not capture exceedances that occur within minutes and are suspected to have negative public health implications. The community has called for standards that consider different averaging times to capture these spikes and subsequent public notice and response.
   2. Salton Sea. Located in Riverside and Imperial counties, the Salton Sea tends to be a major source of hydrogen sulfide emissions due to a large influx of nutrients through agricultural runoff and the declining water levels, which increase the sea’s ability to mix.^{[12],[13],[14],[15]} With summer conditions, monitoring efforts have shown that hydrogen sulfide frequently exceeds the 30 ppb standard, for hundreds of hours over the course of the season.^[16] The humid climate of the region anecdotally exacerbates health effects and the current standard does not take humidity into account. These emissions impact communities already overburdened and suffering respiratory impacts from other emissions originating from the progressively declining Salton Sea, such as aerosolized seawater containing toxins and particulate matter released from the exposed seabed.¹³

Differences between monitoring techniques and deployment locations between local agencies and external groups have highlighted discrepancies in exceedances of the hydrogen sulfide standard.¹⁶ While there are jurisdictional limitations and particular considerations that influence where air quality management districts deploy their monitors, universities and non-governmental organizations have called for more comprehensive monitoring that factors in wind direction.^13,16,[17]

1. Responses involving responsible parties. There have been other incidents of hydrogen sulfide releases in which local agencies were able to identify a responsible party, and their responses have varied. Some of the actions taken in these situations may benefit communities impacted by such “orphan incidents”. For instance, a warehouse fire led to the release of product chemicals in the Dominguez Channel in Los Angeles County, prompting biological processes that resulted in hydrogen sulfide emissions. Technology played a key role in the resolution of this emergency, as a variety of monitoring technologies were deployed such as handheld, mobile, and fixed monitors, and odor neutralizers and aeration devices were used to mitigate emissions.^[18] In 2015, a gas blowout occurred at the Aliso Canyon natural gas storage facility in LA County that led to the release of hydrogen sulfide emissions.^[19] In part, the South Coast Air Quality Management District and CARB responded by establishing criteria for typical air quality levels for hydrogen sulfide at 10 ppb and reporting levels at 5 ppb.^[20],[21]

Whether there is an identified responsible party or not, it is clear that exceedances of the hydrogen sulfide standard tend to generate varied responses from local communities and agencies. Each response is likely custom to particular public health impacts and local needs demonstrated by each community, but not all responses would work for all situations. Reviewing the standard may not change it, as the review would still consider science that originally determined the standard in addition to more recent literature. But more importantly, reviewing the standard may not change how communities respond to these incidents. However, it may be worthwhile to evaluate certain trigger points, their calculations, and responses that correspond to specific community needs.

Comments

1. Purpose of Bill. According to the author, “For generations, families in some of the most economically strained parts of the state have suffered from millions of gallons of sewage and pollution flowing through the Tijuana River and emissions from the Salton Sea. This pollution has been harming our community for decades and yet our air quality standards haven’t been updated in nearly half a century. It is unacceptable that the regulatory standard monitoring the very air our families breathe is so woefully out of date, leaving communities at risk. Making this critical change is a long overdue step towards addressing an issue that has been allowed to fester for decades. It is critical that Sacramento finally act to help our community.”
   
2. Are standards the solution? There may be merit to updating the hydrogen sulfide standard that was deprioritized during the 2000 Standards Review. With 25 years of further research, especially around chronic exposure, additional standards could be beneficial. Moreover, the previous review did not consider the various circumstances across the state that warrant more specificity and nuance. However, the unique situations calling for the proposed standard update fall out of the existing regulatory framework and the development of a new or updated standard would not lead to beneficial outcomes from regulatory action. Thus, rather than updating the existing standards in hope that it will apply at a lower concentration, a new regulatory framework with tailored metrics or trigger points that center public health and response may better meet the needs of impacted communities.
3. Establishing response thresholds. Advisory and response thresholds developed by OEHHA could serve as metrics or trigger points and could consider different averaging times, climates and new research. The 2000 Standards Review referenced that several countries have short-term 30-minute standards and long-term 24-hour standards for hydrogen sulfide.⁸ It is also not clear the extent to which air districts and local agencies consider Acute Exposure Guideline Levels (AEGLs), which are typically used by emergency responders during accidental chemical releases.^[22] AEGLs for hydrogen sulfide have been established at intervals under an hour, and given that emissions data may be solely averaged to compare to the 1-hour standard, this metric may be underutilized. Newly developed thresholds could consider these metrics or develop additional metrics. OEHHA could also consider possible local agency or community responses in the development of such thresholds, including, but not limited to the need for public advisory and notification, reporting, monitoring, regulatory action, mitigation efforts, or relocation. Air districts and other local agencies can adopt the developed thresholds and apply the appropriate response. This will also allow for a uniform approach to such incidents across the state. The author and committee may wish to require OEHHA to develop health-based advisory and response thresholds for hydrogen sulfide and require air districts to adopt any newly developed thresholds.

Given that the review and adoption of a new standard would initiate the rulemaking process within CARB and would involve the input of various stakeholders, any newly established standard may not be purely health-based, but would take into account the regulatory environment. Furthermore, a review of the standard within CARB may not result in any substantial change in the standard. Advisory and response thresholds could center public health and based on any newly developed thresholds, CARB could then adopt updated standards at its discretion. The author and committee may wish to authorize (rather than require) CARB to adopt updated standards, and do so based on any newly developed advisory or response thresholds.

1. A framework for response. Given that these “orphan incidents” can lack a designated regulatory framework, discretion is left to local agencies on how to respond. It can be unclear what the most appropriate response would be, especially since local agencies may lack experience with such incidents and they could vary with context. A review of best practices during similar incidents inside and outside the state could inform guidelines on public notification procedures, local agency response actions and coordination, mitigation technologies, public health assessments, monitoring strategies, data collection, reporting, and resource availability. Establishing guidance could support local air districts and public health agencies and pairing this guidance with newly established response thresholds and existing standards could bring clarity in challenging situations.

There are already similar efforts underway, although it is unclear the extent those efforts take the issues presented here under full consideration. AB 619 (Calderon, Chapter 412, Statutes of 2021) required the California Department of Public Health (CDPH) to develop a plan with guidelines for counties to use during significant air quality events, such as wildfires and related events. This plan is required to be completed by June 2027 (AB 1003, Calderon, Chapter 537, Statutes of 2025), so there is an opportunity to align the needs presented here with the mandated plan or for coordination to reduce duplication. The author may wish to require OEHHA to develop a response framework or guidelines to establish best practices and guidance for threshold exceedance incidents that may impact public health in coordination with related entities.

1. Committee amendments. Staff recommends the committee adopt the bolded amendments contained in comment 3 above.
   

Related/Prior Legislation

AB 1003 (Calderon, Chapter 537, Statutes of 2025) required a plan developed by CDPH with guidelines for significant air quality events to be completed by June 2027, and include public outreach and distribution of the plan.

AB 2851 (Bonta, Chapter 743, Statutes of 2025) required air districts to develop requirements for fence-line air quality monitoring and threshold levels for airborne contaminants associated with metal shredding facilities in consultation with OEHHA.

SB 867 (Allen, Chapter 83, Statutes of 2024) enacted the Safe Drinking Water, Wildfire Prevention, Drought Preparedness, and Clean Air Bond Act of 2024 authorizing the issuance of bonds in the amount of $10 billion to finance projects including, but not limited to drought, flood, and water resilience, coastal resilience, park creation, outdoor access, and clean air programs.

AB 619 (Calderon, Chapter 412, Statutes of 2021) required CDPH to develop a plan with recommendations and guidelines for counties to use in the case of significant air quality events caused by wildfires or other sources.

AB 1597 (Alvarez, 2023) would have authorized funds made available to the California Environmental Protection Agency (CalEPA) for North American Development Bank for loans, grants, and expenditures to address water quality problems arising in the California-Mexico cross-border watersheds. This bill was placed on the suspense file in the Senate Appropriations Committee.

AB 2248 (Eduardo Garcia, 2022) would have made $100 million available from the General Fund to the State Water Board for grants and direct expenditures to address water quality problems arising in the California-Mexico cross-border rivers. This bill was vetoed by Governor Newsom.

SB 1301 (Hueso, Chapter 368, Statutes of 2020) required CalEPA and the California Natural Resources Agency to collaborate to create a Tijuana River Valley Watershed Action Plan to be reviewed and updated on a 3-year cycle.

SB 690 (Hueso, Chapter 381, Statutes of 2019) encouraged the State Coastal Conservancy to prioritize projects identified in feasibility studies conducted by the County of San Diego for the Tijuana River Valley when expending funds to address transboundary flows and pollution in the Tijuana River Valley.

AB 965 (Eduardo Garcia, Chapter 668, Statutes of 2015) established the New River Wate Quality, Public Health, and River Parkway Development Program to coordinate funding and implementation for environmental and health projects and purposes relating to the California-Mexico border region.

AB 1095 (Eduardo Garcia, Chapter 722, Statutes of 2015) required the California Natural Resource Agency to submit a list of shovel-ready restoration projects for the Salton Sea to the Legislature by March 2016.

SB 277 (Ducheny, Chapter 611, Statutes of 2003) enacted the Salton Sea Restoration Act that established a fund for various purposes relating to restoration of the Salton Sea.

SB 25 (Escutia, Chapter 731, Statutes of 1999) required CARB to review all existing health-based ambient air quality standards to determine whether they adequately protect the health of the public, including infants and children, and to revise the highest priority air quality standard determined to be inadequate by December 2002.

SOURCE:

Author

SUPPORT:

Alianza Coachella Valley

Alliance San Diego

Azul

Cactustocloud Institute

City of Imperial

City of Imperial Beach

City of Indian Wells

City of Indio

City of Needles

Coronado Democratic Club

Desert Care Network

Desert Recreation District

Environmental Health Coalition

Imperial Valley Equity & Justice Coalition

Leadership Counsel for Justice and Accountability

Loma Linda University Adventist Health Sciences Center and its Affiliated Entities

Los Amigos De LA Comunidad, INC.

Outdoor Outreach

Palm Desert Area Chamber of Commerce

San Diego for Every Child

Sierra Club

Surfrider Foundation

The Border Group

YMCA of San Diego County

OPPOSITION:

None received

-- END --

1. California Air Resources Board. (2026). National Ambient Air Quality Standards. ↑

2. California Air Resources Board. (2026). California Ambient Air Quality Standards. ↑

3. Office of Environmental Health and Hazard Assessment. (2000). Chronic Toxicity Summary: Hydrogen Sulfide. ↑

4. Office of Environmental Health and Hazard Assessment. (2008). Acute Toxicity Summary: Hydrogen Sulfide. ↑

5. Batterman, S., et. al. (2023). Low level exposure to hydrogen sulfide: a review of emissions, community exposure, health effects, and exposure guidelines. ↑

6. Nuvolone, D., et. al. (2019). Health effects associated with chronic exposure to low-level hydrogen sulfide from geothermoelectric power plants. ↑

7. California Air Resources Board. (2026). Hydrogen Sulfide & Health. ↑

8. Collins, J. and Lewis, D. (2000). Hydrogen Sulfide: Evaluation of Current California Air Quality Standards with Respect to Protection of Children. ↑

9. McLamb, F., et. al. (2024). Evidence of transboundary movement of chemicals from Mexico to the U.S. in Tijuana River Estuary sediments. ↑

10. Cooper, A., et. al. (2025). Identifying wastewater chemicals in coastal aerosols. ↑

11. Rico, B., et. al. (2025). Heavily polluted Tijuana River drives regional air quality crisis. ↑

12. Reese, B., et. al. (2008). Hydrogen sulfide production and volatilization in a polymictic eutrophic saline lake, Salton Sea, California. ↑

13. Centeno, D., et. al. (2025). Hypereutrophication, Hydrogen Sulfide, and Environmental Injustices: Mechanisms and Knowledge Gaps at the Salton Sea. ↑

14. Márquez, C., et. al. (2025). Inadequate Government-Led Water-Quality Monitoring Hinders Improvement Efforts in the Salton Sea. ↑

15. Wilson, J. (2024). This stinks: Salton Sea now emitting bad smells year round. Here’s why. ↑

16. Márquez, C., et. al. (2025). Salton Sea Exceedances of California’s Air Quality Standards Highlight Governance Gaps and Monitoring Needs. ↑

17. Wilson, J. (2025). Study: Salton Sea is emitting foul gas at levels worse than official monitors show. ↑

18. South Coast Air Quality Management District. (2024). Dominguez Channel Odor Event. ↑

19. County of Los Angeles Public Health. (n.d.). Aliso Canyon Disaster Health Research Study: Blowout and Public Health Disaster. ↑

20. South Coast Air Quality Management District. (2016). Aliso Canyon Facility Monitoring Network Plan. ↑

21. South Coast Air Quality Management District and California Air Resources Board. (2016). Criteria for Determining when Air Quality in the Porter Ranch and Surrounding Communities Has Returned to Typical Levels. ↑

22. U.S. Environmental Protection Agency. (2025). Acute Exposure Guideline Levels for Airborne Chemicals. ↑