Noting that the January 2007 fire at Chevron was found by the Root Cause Analysis to have been caused by a pipe that failed due to corrosion, it is interesting that just a year ago, the California Occupational Safety and Health Standards Board, at Chevron’s request, granted a variance to Chevron allowing them to abandon mandatory inspection of corrosion in tanks and pipes, and to pilot a new method called "risk-based inspection" which uses computer models to predict which pipes will need replacement.  As a result, the refinery is now allowed to go literally for decades without conducting physical inspections of pressurized tanks and pipes, while before this change, regular physical manual inspections were required during which pressurized tanks and pipes had to be drained and physically inspected for corrosion and metal thickness.  (OSHSB File No. 04-V-052)  The United Steelworkers (formerly PACE, Formerly OCAW) opposed the variance. 

RICHMOND: CHEVRON STUDY ON JAN. 15 REFINERY FIRE

04/19/07 9:50 PDT

RICHMOND (BCN)

A pipe improperly attached to a crude oil unit at the Chevron refinery in Richmond weakened over two decades and finally failed, causing gas to leak out and ignite, investigators found in their final analysis into a Jan. 15 fire.

The so-called root cause analysis, which the City of Richmond's Industrial Safety Ordinance requires for all accidents that occur at local refineries and chemical plants, was released Wednesday.

The fire began at 5:18 a.m. and the initial wave of firefighters at the scene called in extra support four times before it was declared under control at 8:40 a.m. A shelter-in-place warning was issued for nearby communities as black smoke rose in a billowing column above the refinery.

The Chevron Fire Department, Richmond and El Cerrito fire departments and fire crews from Valero, Shell, Tesoro and Dow all responded to the five-alarm blaze.

Early that morning, workers at the refinery had been preparing the refinery's crude oil processing unit for scheduled maintenance. As a pump was started up, a pipe failed and a mixture of partially processed crude oil and wash oil, which is similar to diesel fuel, was released. Within seconds of the release, the mixture ignited, according to the report.

An operator suffered minor burns during the incident, but no other injuries were reported.

Chevron spokeswoman Camille Priselac said today that the investigators had been unable to conclude the specific ignition source.

"In a refinery there are a lot of potential ignition sources," Priselac said, noting the high temperatures and moving equipment used in the refining process.

Investigators did find that the pipe that failed was part of a seldom-used system employed to clean equipment prior to maintenance. It had been improperly connected to the process plant equipment for 20 or more years, which exposed it to intense heat. Over time, the heat weakened the carbon steel pipe, causing it to eventually fail, according to the report.

A secondary cause of the incident was that an adjacent valve was missing its valve seats, which allowed the pump to send material through the weakened section of pipe at full pressure, according to the report.

All repairs to the crude oil unit at the refinery have been completed and refinery officials have taken, or are planning to take, steps to prevent any similar leaks from occurring in the future both in the crude unit and elsewhere in the refinery, according to the report.

Some refinery-wide equipment inspections and upgrades were expected for completion by the end of May, according to the report.

In spite of the shelter-in-place warning and the visible smoke, no elevated levels of toxins were found in surrounding neighborhoods, according to testing by refinery personnel, county hazardous materials crews and regional air quality officials.

Refinery officials also found that the quantities of sulfur dioxide, nitric oxides, sulfuric acid and hydrogen sulfide that were released as a result of the fire were all below the so-called reportable quantities of hazardous substances, meaning they were not likely to cause any elevated risk to human health.