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Health Advisory

Health Advisory Remains in Effect in Crockett (Oct. 14)

Friday, October 14, 2022

Archived. This is an older press release from 2022 and may not contain the latest information. Please view our current press releases for 2023 items.

Contra Costa Health (CCH) continues to detect elevated levels of hydrogen sulfide in the air and so continues to advise Crockett residents to take precautions due to an ongoing operational issue at the Crockett Wastewater Treatment Plant.

The plant at 1801 Dowrelio Road processes sewage from the community and wastewater from the C&H Sugar refinery. C&H owns the property and through a contractor operates the facility. For information and updates about the operational problem causing the release of hydrogen sulfide in the community, contact C&H at 510-787-2121 or

Contra Costa Health issued its advisory on Oct. 7. At no point has CCH or its partners detected levels of hydrogen sulfide in Crockett’s air that would be considered immediately dangerous.

Air monitoring from CCH’s Hazardous Materials Program (HazMat) on Thursday detected the following:

  • A 1-hour average reading of .025 parts per million (ppm) at Port and Ceres streets, close to the facility
  • A 1-hour average reading of .008 ppm at John Swett High School
  • A 1-hour average reading of .003 ppm at Carquinez Middle School

While these concentrations of hydrogen sulfide are lower than the .03 ppm threshold that triggered this advisory, some people may experience symptoms such as headaches, nausea, or burning eyes if exposed over long periods. Anyone experiencing severe or prolonged symptoms should contact their healthcare provider.

Contra Costa Health will be continuing to monitor the situation and take readings in the area over the weekend. We will alert the community if we begin to detect levels of hydrogen sulfide in the Crockett area that may pose a significant immediate health threat. Otherwise, we will provide our next update on Monday, Oct. 17.

Due to the long-running nature of the release from the plant and the variability of the presence of chemical due to geography, weather and proximity to the plant, the health department continues to recommend that residents to take steps to protect themselves from symptoms of exposure.

Recommendations include:

  • Stay indoors with doors and windows closed to reduce exposure, particularly people experiencing minor symptoms
  • Use commercially available carbon air filters to reduce levels of hydrogen sulfide indoors
  • Contact your healthcare provider if experiencing serious or persistent symptoms

Smelling hydrogen sulfide (a rotten-egg or sewage odor) is not necessarily an indicator that concentrations in the air are high enough to pose a health risk.

Masks are not effective protection from hydrogen sulfide exposure.

Crockett residents have made numerous complaints about odors caused by hydrogen sulfide to public agencies that regulate the treatment plant. For information about regulatory action related to the plant, contact the Bay Area Air Quality Management District at 415-749-4647.

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  • CCH Media Line,