SAN FRANCISCO (AP) -- Tests of pipe samples from Chevron Corp.'s El Segundo refinery found corrosion to an extent similar to the pipe that failed and caused a large fire at the company's Richmond facility, a report released Thursday found.
The tests found up to 60 percent wall loss in a pipe at the El Segundo refinery that processed the same type of crude as its sister facility in Northern California, according to the U.S. Chemical Safety Board and California Division of Occupational Safety and Health.
Chevron voluntarily inspected the pipes at its El Segundo facility after an Aug. 6 fire in Richmond caused by a corroded, 1970s-era pipe.
The resulting vapor cloud engulfed 19 workers, who escaped injury, and the fire that followed sent a plume of black smoke into the sky which drifted over nearby neighborhoods.
Some 15,000 residents sought medical treatment for breathing and eye irritation problems, though just 20 were hospitalized, according to a government investigation.
Because the El Segundo and Richmond crude units are nearly identical facilities, Chevron took the El Segundo unit out of service for inspections after the fire.
Tests ordered by Cal/OSHA found that corrosion in El Segundo had damaged pipe samples in ways similar to the one that failed in Richmond, though not as extensively. Cal/OSHA also issued 25 violations and nearly $1 million in fines associated with the Richmond fire.
Chevron replaced the pipes in September.
Still, Rod Spackman, a spokesman for Chevron's El Segundo refinery, said the company believed the corroded pipes at the facility were still "suitable for continued operation" even after inspecting them.
"However, in an abundance of caution, we nevertheless replaced portions of the piping system," Spackman said.
Both the El Segundo and the Richmond refineries were built in the late 1970s.
They process crude oil that has sulfur in concentrations that are unsafe for the carbon steel pipes, some of which date back to when the refineries were constructed, according to the chemical board.
The sulfur is corrosive to the carbon steel pipes, and was identified as the cause of the damage that led to the accident in Richmond.
"The tests underscore the importance of new actions to eliminate this hazard through requiring inherently safer designs and materials, rather than relying on inspections alone to find developing safety problems," Rafael Moure-Eraso, the chemical board's chairman, said in a statement.
Chevron said it believed the CSB was overstating the danger posed by the corrosion in pipes at its El Segundo facility.
"While the report determines that the replaced piping components had general thinning consistent with ... sulfidation corrosion, we believe the CSB's characterization of the extent of this corrosion ... is incomplete and leads to the false impression that the El Segundo pipe was in imminent danger of experiencing a failure," Spackman said in a statement.
The company said it is cooperating with state and federal investigations, and implementing stricter inspections and oversight of its facilities.
Cal/OHSA has also given the go-ahead to Chevron to restart the rebuilt crude unit destroyed in last year's fire. The company expects that to happen before the end of June.