Critical Update to Hydrogen Sulfide Air Standards Signed Into Law as Federal Report Acknowledges Public Health Risk
SACRAMENTO – Recently, California Governor Gavin Newsom signed into law Senate Bill 58 by Senator Steve Padilla (D-San Diego), which will direct the California Air Resources Board to update California’s air quality standard for hydrogen sulfide (H2S), a gas that is found at high concentrations in the Tijuana River Valley and the Salton Sea region. California’s hydrogen sulfide standard has not been updated since 1969. Just last week, the Agency for Toxic Substances and Disease Registry, for the first time found hydrogen sulfide in outdoor air near the Tijuana River reached levels that could harm people’s health.
H2S is a colorless gas that smells of rotten eggs. It is commonly found in natural gas and oil extraction and is a natural emission from geothermal fields but is also present during bacterial decomposition of human and animal waste. Exposure to H2S can cause headaches, nausea, eye and respiratory irritation and current evidence indicates that chronic exposure can contribute to persistent respiratory and neurological impacts, with heightened susceptibility among children, older adults, and individuals with preexisting health conditions. The gas is found in exceptionally high quantities in the Tijuana River Valley and the Salton Sea region.
These exposures disproportionately affect vulnerable and environmentally overburdened communities, including low-income households, immigrant communities, Latino and Tribal populations, and areas already experiencing elevated rates of respiratory and other health conditions, exacerbating existing health inequities. Yet, the state’s current framework for Hydrogen Sulfide lacks incorporation of the unique nature of the Salton Sea and the Tijuana River Valley resulting in a lack of clear, consistent guidance on appropriate responses to address hydrogen sulfide exposure and protect public health in our communities.
The California Ambient Air Quality Standard (CCAAQS) for H2S was established by the California Air Resources Board (CARB) in 1969, at 0.03 parts per million (30ppb), averaged over one hour. This standard was developed to control odor nuisance, not to protect public health. The last review of the standard occurred in 1984, when the California Department of Public Health concluded that the existing standard was adequate. It concluded that tightening the standard would have only a “disappointingly small effect” on reducing odor intensity. The 1984 review focused on odor detectability and annoyance thresholds, not toxicological or epidemiologic data. No comprehensive review has been conducted in over four decades, despite advances in understanding chronic and low-level H2S health risks.
“San Diegans suffer from the effects of overexposure to this gas every day,” said Senator Padilla. “This report just confirms what residents have known all along. We owe it to these communities to make this long overdue update. This law is just the start of critical protections the South Bay deserves.”
SB 58 directs the California Air Resources Board (CARB), 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.
The framework is intended to provide a more comprehensive evaluation of hydrogen sulfide exposure by providing a more accurate understanding of acute and chronic impacts on vulnerable populations, to improve identification of gaps, and inform approaches to address chronic exposure. In doing so, SB 58 will 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.
Senator Padilla has authored several measures to address the public health crisis at California’s Southern Border. To read more about Senator Padilla’s previous efforts to address the pollution in the Tijuana River Valley, click here, here and here.
Senate Bill 58 is supported by the environmental justice community and local leaders.
“Thank you to State Senator Steve Padilla for his steadfast leadership and dedication to the residents of South San Diego, and to Governor Newsom for signing SB 58 into law. This is a monumental victory for public health and environmental justice across our region,” said San Diego County Supervisor Paloma Aguirre. “Families in South County and the Tijuana River Valley have borne the heavy burden of toxic hydrogen sulfide spikes without a unified, aggressive response strategy. By bringing together state agencies, local leaders, and community advocates, SB 58 helps us respond quickly to toxic spikes and protect our families. This law marks a vital turning point, and I look forward to working alongside our state and local partners to put these critical protections into motion."
"No one should have to endure ongoing exposure to hydrogen sulfide because of where they live, work, or go to school,” said Sarah Davidson, Clean Border Water Now Campaign Manager at San Diego Surfrider Foundation. “Yet, communities in and around the Tijuana River Valley continue to face conditions that put their health at risk simply by breathing. SB 58 takes an important step toward giving residents and public health officials the information they need to understand and respond to unsafe levels of hydrogen sulfide exposure. We are grateful to Senator Padilla, the CA Legislature, and Governor Newsom for recognizing this urgent public health need and taking action to help protect impacted communities.”
"Coastkeeper commends Senator Padilla and his bill co-sponsors for their leadership on this critically important public health issue," said Phillip Musegaas, Executive Director of San Diego Coastkeeper. "This legislation is an essential first step towards setting standards to protect local residents' immediate and long term health and quality of life."
“The Tijuana River Coalition applauds Senator Padilla, the state legislature and Governor Newsom for signing SB 58 into law,” said Courtney Baltiyskyy with the Tijuana River Coalition. “It has been two years since acclaimed San Diego-based researchers identified high levels of hydrogen sulfide in the Tijuana River Valley, confirming what community members had been reporting for years: something is not right with the air they breathe. SB 58 is a step forward in establishing community-based standards and improving responses to toxic gases. We hope future commitments from the state will help make the Tijuana River Valley and surrounding beaches safe places to live, work, play, and learn.”
“New research showing why hydrogen sulfide in the Tijuana River Valley is a threat to human health illustrates why we need immediate state and federal action to stop the flows of sewage and toxic waste in the Tijuana River,” said Serge Dedina, Ph.D., Executive Director at WILDCOAST.
SB 58 passed the Senate unanimously 40-0 and the Assembly with bipartisan support 79-0. The bill becomes law January 1st, 2027
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Steve Padilla represents the 18th Senate District, which includes the communities of Chula Vista, the Coachella Valley, Imperial Beach, the Imperial Valley, National City, and San Diego. Prior to his election to the Senate in 2022, Senator Padilla was the first person of color ever elected to city office in Chula Vista, the first Latino Mayor, and the first openly LGBT person to serve or be elected to city office. Website of Senator Steve Padilla: https://sd18.senate.ca.gov/