From the Contra Costa Health department:
Contra Costa Health (CCH) continues to advise Crockett residents to take steps to protect their health due to elevated levels of hydrogen sulfide coming from the Crockett Wastewater Treatment Plant.
Air monitoring data from Monday and Tuesday from CCH’s Hazardous Materials Program (HazMat) show concentrations of the chemical that may cause symptoms such as headaches, nausea and irritated eyes in people exposed to it for long periods.
CCH and its partners have not detected levels of hydrogen sulfide in Crockett’s air that would be considered immediately dangerous to public health.
The threshold at which hydrogen sulfide in the air may cause symptoms is .03 parts per million (ppm). The Bay Area Air Quality Management District (BAAQMD) measured a 1-hour average reading of .036 ppm near the plant on Friday, Oct. 7, prompting the health advisory from CCH.
On Tuesday, Oct. 11, a Hazardous Materials team collected a one-hour average reading of .045 ppm near Port and Ceres streets, directly east of Interstate 80 from the plant.
Commercially available carbon air filters, also known as activated charcoal air filters, are effective at reducing levels of hydrogen sulfide indoors. Masking is not effective protection.
CCH recommends anyone experiencing minor symptoms to stay indoors with windows and doors closed. People experiencing serious or persistent symptoms should contact their health provider.
Levels in the air may vary based on location, weather and proximity to the plant. Smelling hydrogen sulfide (a rotten-egg or sewage odor) is not an indicator that concentrations in the air are high enough to pose a health risk.
The Contra Costa County Office of Emergency Services and HazMat provided 40 indoor air filters to the John Swett Unified School District for use at John Swett High and Carquinez Middle schools.
On Tuesday, HazMat measured a 1-hour average reading of .0031 ppm outdoors at John Swett High, and .0015 ppm outdoors at Carquinez Middle.
CCH will release updated air quality data as it becomes available.
The elevated levels of hydrogen sulfide in Crockett’s air are the result of a weeks-long operational issue at the plant, 1801 Dowrelio Road, which 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.
CCH is responsible for providing public health information and guidance about what actions to take to stay healthy and safe. 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 firstname.lastname@example.org.
Crockett residents have made numerous complaints about odors caused by hydrogen sulfide to public agencies that regulate the treatment plant, including BAAQMD. For information about regulatory action related to the plant, contact the Bay Area Air Quality Management District at 415-749-4647.
The Crockett Improvement Association will host a public meeting at 7 p.m. Thursday, Oct. 13, regarding the situation at the plant at Crockett Community Center, 850 Pomona Ave.