A preliminary health assessment from the Bay Area Air District released this week found that residents living near the Chevron refinery in Richmond face a higher risk of cancer and other diseases.
If the results of the assessment are confirmed, Chevron will have to implement a plan to reduce the health risks or install pollution controls at the refinery.
The Bay Area Air District is the agency responsible for protecting air quality in the region. In 2017, the district adopted a new rule requiring facilities that could pose high health impacts to undergo a preliminary health assessment to quantify potential health risks.
The air district identified the Chevron refinery as one such facility and commissioned the preliminary health assessment.
Experts from the agency conducted multiple studies and collected samples between 2017 and 2025 to prepare the assessment, which was released Tuesday.
The assessment estimated a maximum cancer risk of 37 in a million, meaning that 37 additional people out of a million could develop cancer over a lifetime of exposure to air pollution from the refinery.
This exceeds the district’s threshold of 10 in a million, beyond which facilities must implement a plan to reduce health risks, according to a news release from the agency.
The risk of other non-cancer health effects from short-term exposure was also found to exceed the district’s threshold.
The report states that most of the cancer risk is due to benzo[a]pyrene, a pollutant that escapes through small leaks at pipe fittings and storage tanks, while the short-term health risks are mostly due to benzene from the refinery’s wastewater treatment system.
The district is now requesting public input and will modify the risk estimates based on community comments.
“These findings give the Richmond community clear, science-based information about the health risks from refinery air pollution emissions,” Philip Fine, executive officer of the Bay Area Air District, said in the news release. “Community input is essential before we finalize this assessment because the people who live closest to the refinery have the most at stake.”
If the results of the preliminary health assessment hold after reviewing public comments, Chevron will be required to implement a plan to reduce pollution or install the best available pollution controls, the district’s news release said.
“The Air District’s own analysis acknowledges that the assumptions driving most of its cancer-risk estimate may overstate actual refinery emissions,” said Ross Allen, a spokesperson for Chevron.
“We agree and have already found that the assessment includes equipment that is no longer operating and assumptions that do not reflect actual refinery conditions. These issues need to be resolved before this preliminary estimate is treated as an accurate model of community health risk,” Allen added.
Recent air quality enforcement actions
In June 2025, the district reached an agreement with Chevron on a new air pollution monitoring system at the Richmond refinery to better monitor hydrogen sulfide, a smelly and potentially dangerous gas.
Chevron also agreed to pay a $100,000 fine for insufficient monitoring of the chemical at the time.
Then, in December 2025, the district imposed a $900,000 fine on Chevron after the company failed to make upgrades to its pollution monitoring systems as mandated by a district audit.
Responding to Tuesday’s preliminary health assessment, Richmond Mayor Eduardo Martinez said in a separate news release that the report provides a quantitative basis for preexisting public sentiment.
“As a city, we will do everything within our power and ability to ensure that any corporation operating within our city limits does so with environmental and social responsibility,” he said.
The Bay Area Air District will hold a community meeting to explain the report’s findings and the procedure for submitting public comments on Sept. 21 at 5:30 p.m. at the Richmond Memorial Auditorium & Convention Center.
Community members can submit public comments on the issue until Nov. 23.