Richmond’s city council is scheduled to discuss the potential environmental impacts of a half-century-old technology that could drastically reduce toxic emissions at the Chevron oil refinery, at its meeting this week.
The device, known as a “wet gas scrubber,” would use water to remove pollutants from gas exhaust that otherwise would be released directly into Richmond’s air. The Bay Area Air District instructed Chevron to install a scrubber in 2021 to comply with its emissions targets, but the project has been delayed by lawsuits filed by the oil company and lengthy environmental reviews.
The debate over the wet gas scrubber is just the latest in a long, drawn out process to reduce oil refining emissions in Richmond and west Contra Costa County, which state regulators have identified as one of the most polluted areas in California.
Residents and environmental groups over the last few months have raised concerns over the project as it’s gone through an environmental review process mandated by the California Environmental Quality Act (CEQA), while also acknowledging the technology’s potential to drastically improve local air quality.
Chief among the concerns are the amount of water used in the scrubbing process, how Chevron will handle the highly contaminated soil where the scrubber is expected to be built, and the potential for increased light and noise pollution.
City officials are expected to address public comments submitted during the environmental review process at a public meeting in the Richmond city council chambers at 6:30 p.m. on Nov. 5. The city has also already done so in a document it released earlier this month.
What is a wet gas scrubber?
Wet gas scrubbing is a method developed in the 1970s by ExxonMobil that can be tailored to remove a host of pollutants during fluid catalytic cracking, a process used in oil refining. These pollutants include particulate matter, sulfur dioxide and nitrogen oxides, according to Babcock & Wilcox Enterprises, which licenses the technology.
The scrubber uses a solution of water and sodium hydroxide, commonly known as lye, to remove sulfur compounds and particulates from the gas before it’s released into the air. The company touts that its wet gas scrubber can easily be retrofitted into existing refining operations, such as Chevron Richmond.
The liquid byproduct of the scrubbing process is a simple mix of water and sodium sulfate, an inorganic salt used in household detergents, paper manufacturing, and glass production, according to the company.
Most importantly, the wet gas scrubber is expected to reduce the refinery’s emissions of PM 2.5, a pollutant that is produced by the burning of fossil fuels, heavy industry and wildfires. Roughly 30 times smaller than the diameter of a human hair, the particles are particularly dangerous because they can permeate the blood-brain barrier and become embedded in the lungs and other vital organs.
The U.S. Environmental Protection Agency in 2024 lowered the annual exposure level of PM 2.5 — the highest number they consider safe for people’s health — to 9 micrograms per cubic meter. Recent testing of Richmond’s air has shown levels between 7.4 and 10 micrograms per year.
The Bay Area Air District has pinpointed Chevron’s refinery as Richmond’s single largest source of PM 2.5, and estimates that PM 2.5 emissions result in more than 11 premature deaths in the surrounding neighborhoods per year.
More recently, the air district has said that Point Richmond, the area south of the refinery, is exposed to emissions that are reportedly 3.5 times the level requiring correction, and pose an increased risk of cancer to people who live, work and go to school there.
Wet gas scrubbers are now required at Bay Area refineries
To start reducing the most harmful forms of air pollution, the Bay Area Air District adopted Rule 6-5 in July 2021, which set hard limits on the amount of particulate matter allowed on any given day by oil refineries. This included a requirement that Chevron Richmond and the Martinez Refining Company install wet gas scrubbers.
In expressing his support of Rule 6-5 in 2021, Benicia Mayor Steve Young wrote that the wet gas scrubber that Valero voluntarily installed at its refinery in 2010 had resulted in a “significant reduction in the overall emissions of criteria pollutants,” like PM 2.5.
Chevron and the Martinez Refining Company initially challenged Rule 6-5 by suing the air district. Chevron said the district’s rule-making process was “fundamentally broken” and that the ruling was “another example of how California policies have led to a hostile business environment for manufacturers.”
The companies eventually withdrew their lawsuits, settling with the air district for a combined $138 million in February 2024. The settlement included notices of violation the air district had levied against Chevron from 2019 to 2023, and established a Richmond-area Community Air Quality Fund. Residents and the city began deciding what local projects will be funded by that settlement earlier this year, including more parks, and projects to create safer streets and cleaner air.
The scrubber should vastly reduce pollution. But there’s disagreement over how quickly to proceed.
Last week, the city of Richmond released a report addressing questions and concerns brought up during the public comment period for the wet gas scrubber’s latest addendum to its environmental impact report, the first of which went up for review in 2018.
While CEQA doesn’t require public review for an addendum to an approved EIR, the city did it anyway.
In an email, Richmond resident Sally Tobin, a retired Stanford professor, inquired about the amount of potable water the scrubber would need and about the noise and light pollution it would cause.
In its response, the city said the wet gas scrubber would use 370,000 gallons of potable water per day from the East Bay Municipal Utility District. But if another proposed part of the project — the Isomax Cooling Water Tower — is approved, it said, Chevron can use recycled water instead of potable water for the scrubber.
The light and noise levels generated by the project are expected to be within permitted ranges, according to the city.
Michael Herz, an environmental activist and the founder of San Francisco Baykeeper, an environmental protection group, asked what will happen to the waste collected and created during the scrubbing process. The city replied that solids would either be disposed of in a landfill or recycled at a cement kiln, and liquid would be treated at the refinery’s wastewater treatment plant before being released into the adjacent San Pablo Bay.
The activist group Communities for a Better Environment has been among the most vocal critics of Chevron’s actions and pollution in Richmond, and its public comments during the environmental review focused on the project’s potential to have negative environmental consequences if rushed.
“Despite our position that this long overdue and life-saving technology should be installed, the environmental impacts of the construction and operation of the technology must be properly understood and adequately mitigated,” staff attorney Kerry Guerin and program director Shiva Mishek wrote on behalf of the group. “A good thing cannot be allowed to be done poorly.”
CBE asked how the scrubber would be powered, and whether Chevron planned to draw electricity from its Cogeneration Plant, which burns refinery fuel oil. CBE described the nearly 16,000 megawatt-hours per year that will be required to run the scrubber as “massive.”
Since Chevron’s Cogeneration Plant accounts for roughly 20% of the refinery’s PM emissions, the group said, an increase in power would also raise PM emissions. The city replied that the plant in question is already outputting at capacity and that any extra electricity needed would come from PG&E.
CBE also questioned what will happen to polluted groundwater at the site that’s disturbed during construction. “It is among the most contaminated sites in all of California, and the Project requires that the soil be excavated and transported through the rest of Richmond,” CBE wrote.
CBE suggested that the city should require Chevron to soil-test and report back monthly. “For the City to not impose this requirement would be to be willfully ignorant and put residents’ health and safety in danger,” CBE wrote.
In its response, the city said the soil would be “treated as contaminated unless laboratory testing confirms it to be non-hazardous” in accordance with state and federal law and be disposed of properly at places like the Buttonwillow Landfill in Kern County.
CBE, too, brought up noise concerns, particularly over what hours construction would be done. The city replied that it had given the project a waiver allowing construction to begin as early as 6 a.m., but that the loudest activities, like pile-driving, would be reserved for typical working hours.
Other public comments lauded the addition of the wet grass scrubber as a needed step forward.
Point Richmond resident Jeff Kilbreth, a former planning commissioner who sits on the steering committee for AB 617 — a state-funded program that aims to reduce air pollution in some of California’s most toxic communities, including the Richmond-San Pablo area — urged the city council, planning commission and air district to “do everything in your power to expedite rapid approval” of the scrubber.
In his written comment, he said the project “will result in the most significant single amount of pollution reduction in well over 30 years and very likely the most significant single pollution reduction possible in the future,” outside of the refinery cutting production by 40% or shutting down entirely.
In his letter to the city, Kilbreth also credited Chevron engineers for producing a high-quality project description. “Chevron often complains about the slowness of permit approvals,” he said, “so it is important to appreciate well done applications and to in response produce permits quickly when possible.”
“This project is an enormous regulatory success,” Kilbreth said.
