One month after officials at Tesoro Corp.’s Golden Eagle Refinery in the Bay Area denied federal investigators access after workers were sprayed with sulfuric acid, two more workers were doused in the same area of the plant.

The incident Monday was thought to be less serious than the one February 12, but that couldn’t be confirmed because investigators for the U.S. Chemical Safety Board (CSB) say they still lack critical information from the first accident.

Workers in the latest incident, in Martinez, were wearing protective suits when sprayed but acid apparently dripped on them as they removed the clothing. The two men were hospitalized, Tesoro said, with what were described as non-life-threatening injuries. One was quickly released and the other was held overnight, according to the San Francisco Chronicle.

The February incident set up a confrontation between the Safety Board and Tesoro when, after an initial cursory look at the facility, investigators were denied access to workers and records. Tesoro maintained in a press release that the board lacked the right to investigate because it was a “personal safety incident that did not result in serious injuries or substantial property damage.”

The board responded by issuing a subpoena for the records they wanted. It got some, but not all, of the information and access it sought, and said some of the evidence had not been preserved by the time they got back into the plant. Those workers had not been wearing protective suits, and other workers told investigators that wasn’t unusual. They were treated for first- and second-degree burns and released the same day.

Although Tesoro characterized the release of acid in the first incident as minor, Safety Board spokeswoman Hillary Cohen told the Chronicle the incident was “hardly the minor release that Tesoro has been describing to the public.” She said one document obtained by the board indicated that an estimated 84,000 pounds of sulfuric acid were released.

When Tesoro first blocked the investigators, board Managing Director Dan Horowitz told the Contra Costa Times, “We've certainly faced our share of jurisdictional challenges, but I can't think of another refinery or chemical plant that has taken a position that injuries aren't serious enough for us to investigate and that we lack jurisdiction.”

The February incident is being investigated by California’s Division of Occupational Safety and Health (Cal/OSHA) in the Department of Industrial Relations.

The board, which is an independent federal agency, does not issue citations or fines. It works to determine the causes of U.S. chemical plant accidents and issues reports, which often range beyond the investigation at hand to make broader safety recommendations.  

–Ken Broder   

To Learn More:

New Acid Accident Burns 2 Workers at Tesoro Refinery (by Jaxon Van Derbeken and Henry K. Lee, San Francisco Chronicle)

Sulfuric Acid Spill at Tesoro Refinery in Martinez (by Lisa Fernandez, NBC Bay Area)

Two Workers Sprayed by Acid at Martinez, California Tesoro Refinery (by Koustav Samanta and Erwin Seba, Reuters)

Bay Area Refinery Bars Federal Inspectors after Accident (by Ken Broder, AllGov California)