California Bill Aims to Strengthen Regulations for Toxic Tijuana River Gas

State Senator Steve Padilla's legislation would require new public health standards and give local air districts more power to protect residents.

Apr. 14, 2026 at 12:57am

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A serene, photorealistic painting of a solitary gas monitoring station in a rural, sun-dappled landscape, conveying a sense of quiet contemplation about the environmental challenges facing the region.As toxic gas continues to plague the Tijuana River Valley, new legislation aims to strengthen regulations and enforcement to protect public health.San Diego Today

Toxic hydrogen sulfide gas from the sewage-polluted Tijuana River has repeatedly exceeded safe levels in the South Bay region of San Diego, prompting State Senator Steve Padilla to introduce a bill that would require the state to develop new public health standards for the gas and give local air pollution control districts more authority to protect the public.

Why it matters

The Tijuana River has long been a source of pollution and environmental hazards for communities on the U.S. side of the border, and the recurring issue of toxic hydrogen sulfide gas highlights the need for stronger regulations and enforcement to safeguard public health. Padilla's bill aims to address the lack of clear federal and state standards for acceptable hydrogen sulfide exposure levels.

The details

Padilla's bill, SB 58, would require the state Office of Environmental Health Hazard Assessment to develop a new public health hydrogen sulfide standard, direct the state to hold public workshops on the matter locally, and give more power to local air pollution control districts to protect the public from harm. Currently, the San Diego Air Pollution Control District can only alert the community if hydrogen sulfide reaches 30 parts per billion, but research suggests that threshold is too high and prolonged exposure to just 1.4 ppb could make people sick.

  • On Sunday night, levels of hydrogen sulfide spewing from the Tijuana River exceeded what the state says is safe for sensitive groups.
  • In January, Padilla presented the bill to the State Senate Committee on Environmental Quality, arguing that the state needs to 'lower the standard and strengthen enforcement'.
  • The bill passed the Senate on January 26 and is now awaiting hearings in the California Assembly.

The players

Steve Padilla

A Democratic state senator representing California's 18th district, who introduced SB 58 to strengthen regulations for toxic hydrogen sulfide gas from the Tijuana River.

San Diego Air Pollution Control District

The local agency that alerts the community when hydrogen sulfide levels exceed 30 parts per billion, though research suggests this threshold is too high.

Calpine Corporation

A privately-held natural gas and geothermal power company that logged concerns about Padilla's bill at the January committee hearing, wanting to 'watch this and make sure it doesn't have implications to the geothermal industry'.

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What they’re saying

“We don't have a standard that reflects the current science. The state needs to 'lower the standard and strengthen enforcement'.”

— Steve Padilla, State Senator

“We just want to watch this and make sure it doesn't have implications to the geothermal industry.”

— Theo Pahos, Representative, Calpine Corporation

What’s next

The bill already passed the Senate on January 26 and is now awaiting hearings in the California Assembly.

The takeaway

This case highlights the ongoing environmental and public health challenges posed by the Tijuana River's pollution, and the need for stronger state-level regulations and enforcement to protect vulnerable communities on the U.S. side of the border from toxic gas exposure.