RICHMOND -- Federal investigators say last week's massive blaze at Chevron's Richmond refinery was a "near disaster" that could have killed more than a dozen workers trying to fix an old, leaky pipe, but a review of air pollution violations, accidents and fires at Contra Costa's four refineries show the San Ramon-based oil giant is not the worst offender.
The Aug. 6 fire in a crude oil refining unit burned and billowed smoke for hours, prompting residents in nearby communities to seek shelter indoors. More than 5,700 people visited doctors or hospitals, complaining of breathing problems and throat and eye irritation as of Friday, according to county health officials.
The fire has ratcheted up public attention on Chevron's Richmond plant, the largest of five in the Bay Area and the oldest on the West Coast. But overall, area refineries have improved their environmental and safety performance in the past decade.
Regulators have no single yardstick by which to judge an oil refinery's overall environmental record, but some suggest the 110-year-old Richmond refinery is neither at the front nor the back of the pack.
Since 1999, Chevron in Richmond had eight major pollution incidents, five of which were fires. That is fewer than two of the other three refineries in Contra Costa County, according to records with the county Hazardous Materials Program.
The Tesoro plant in north Concord had 23 major accidents, including 10 fires; ConocoPhillips in Rodeo had 13 major incidents, only one of which involved a fire; and Shell had nine major accidents, including two fires. While Chevron has maintained consistent ownership of the refinery since its start, the other three refineries have changed hands multiple times during the past decade.
Of the four refineries, Chevron racked up the highest number of Level 3 accidents -- those with a fatality, serious injury and major damage -- during that time period.
Accidents at the plant since 1999 caused thousands of people to seek medical attention, far more than the other three refineries.
Randy Sawyer, head of the county's hazardous materials program, and other county officials said they are concerned about the latest Chevron fire and want to hear detailed explanations for how to prevent future incidents.
U.S. Chemical Safety Board investigators said Saturday more than a dozen refinery workers were engulfed in a combustible vapor cloud released when insulation was removed from the leaky pipe and could have died upon ignition. They also questioned why the 1970s-era pipe was not replaced last November when an adjacent and corroded pipe was removed. The team also plans to look at whether the unit should have been shut down before crews started working on the leaky pipe.
The smoke from the ensuing inferno was thick with particulate matter, and late last week air quality regulators revealed that one air sample in El Cerrito contained high concentrations of acrolein, a respiratory and eye irritant, correcting an earlier statement that no significant levels of pollutants had been found. Even so, the levels were within the range normally found in the Bay Area, regulators said.
In the long term, though, Sawyer said Chevron does not stand out as a poor performer in an industry that is inherently risky because of the high volumes of flammable and toxic materials it handles.
"Generally, Chevron has really good safety practices in place," said Sawyer, whose program enforces a county industrial safety ordinance.
One refinery watchdog said its hard to compare Chevron with other refineries. "They (Chevron) have shown they can reduce emissions in response to community pressure," said Greg Karras, senior scientist with Communities for a Better Environment. "They also can be stubborn because they are powerful and can get their way."
Chevron had the second-lowest total of air pollution violations among the five Bay Area refineries between 2007 and 2011, according to a report by the region's air pollution agency.
Chevron had 95 violations, while the low was 87 violations for the Shell oil refinery in Martinez, according to the Bay Area Air Quality Management District.
Valero in Benicia (Solano County) had 224 violations, Tesoro had 164 and ConocoPhillips had 130 violations, the air district reported.
The violations include technical errors -- such as a monitor not working correctly -- as well as excessive emissions from the plant.
Using another environmental yard stick, the Chevron refinery reported that it had the second-lowest total of toxic materials released or disposed of among the five Bay Area refineries during 2010.
Chevron reported 575,660 pounds, lower than the 1.27 million pounds from Valero in Benicia, 1.2 million pounds from ConocoPhillips, and 692,536 pounds from Shell in Martinez, according to the federal Environmental Protection Agency's toxic release inventory.
The Tesoro refinery had the smallest amount with 469,669 pounds, according to the federal report.
According to the EPA, the Chevron refinery is still under an agency order to cut sulfur dioxide and nitrogen oxide emissions from the plant.
Staff writers Sean Maher and Paul Rogers contributed to this report. Contact Denis Cuff at 925-943-8267. Follow him at Twitter.com/deniscuff.