Cal-OSHA investigating Santa Rosa tanker explosion at Kaiser medical campus

Santa Rosa authorities and state workplace safety investigators continued their investigations Thursday into the explosion of a tanker truck outside a Kaiser Permanente medical office, the results of which won’t be known for weeks or months.

The explosion, which occurred Wednesday as the truck was delivering liquid oxygen to a Kaiser office on Old Redwood Highway in north Santa Rosa, is under review by the state Division of Occupational Safety and Health, better known as Cal/OSHA.

The agency has up to six months to issue citations for any violations of workplace safety and health regulations in the blast, which caused significant injuries to the driver and forced the evacuation of two medical offices located about a mile north of the main Kaiser hospital site in Santa Rosa. ?Highway 101 and Old Redwood Highway also were closed for about two hours.

Santa Rosa firefighters and police investigators are reviewing the incident as well.

“All three agencies are playing an equally important role as we sort through the evidence in this case and find out exactly what occurred in this investigation,” said Santa Rosa police Lt. John Cregan.

Police investigators won’t be finished with their work for at least a few weeks, Cregan said.

The exact cause of Wednesday’s explosion remains unclear, but authorities have said it occurred as the driver was trying to deliver the oxygen to an on-site tank. The driver, a 36-year-old Sacramento man whose name hasn’t been released, suffered significant injuries and remained hospitalized Thursday in stable condition, according to Cregan.

Equipment on the rear end of the Kaiser building where the explosion happened sustained minor damage, and debris also damaged numerous cars nearby, Cregan said.

One of the two medical offices that were evacuated, Building 4 at 3925 Old Redwood Highway, opened for business as usual Thursday. Medical Office Building 5 at 3975 Old Redwood Highway - where the explosion occurred - was closed.

Building 5 will be closed again Friday, “pending concluding regulatory and fire inspections,” Kaiser announced Thursday evening.

Kaiser said it is contacting patients who had appointments or outpatient surgeries scheduled for Friday at Building 5 to make other arrangements. Services provided at the site include outpatient surgery care, as well as physical therapy and radiology.

It’s not clear how many people were evacuated as a result of Wednesday’s explosion, which prompted a large response from Santa Rosa firefighters and police, as well as the CHP.

Fire dispatchers were told of the explosion about 2:30 p.m., with initial reports suggesting the trailer truck crashed into a building at the medical office campus. Santa Rosa Assistant Fire Marshal Paul Lowenthal said an investigation of the site didn’t show any evidence to support that claim.

A truck with a logo for Matheson, a New Jersey-based industrial and medical gas supplier, was at the scene of the explosion. The back portion of the vehicle appeared burned and some metal parts were disfigured.

Attempts to reach Matheson were not successful Thursday. Lowenthal said Wednesday that representatives of the company were working closely with police and fire officials to resolve the situation.

A Cal/OSHA representative was also on site Wednesday, Lowenthal said.

Staff Writer Nashelly Chavez can be reached at 707-521-5203 or On Twitter @nashellytweets. Staff Writer J.D. Morris can be reached at 707-521-5337 or On Twitter @thejdmorris.

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