The U.S. Chemical Safety Board (CSB) has decided to pursue a full investigation to determine the causes of last week’s fire at the Chevron oil refinery in Richmond, California, northeast of San Francisco.
A CSB team numbering seven investigators arrived in at the refinery on Wednesday and has since been conducting witness interviews and reviewing documents at the site. CSB structural and industrial safety experts will reach the site today Monday to prepare for safe entry by investigators into the immediate area of the fire.
The fire occurred when a combustible hydrocarbon liquid known as “gas-oil” leaked from an eight-inch pipe connected to a crude oil distillation tower in the refinery’s crude unit. Workers initially noted the leak and were in the process of attempting repairs on piping connected to the still-operating crude oil distillation tower when the leak suddenly intensified. Due to the high temperature of the material in the tower (in excess of 600 degrees Fahrenheit) the gas-oil immediately formed a large flammable vapor cloud.
“Witness testimony collected by CSB investigators indicates that a large number of workers were engulfed in the vapor cloud,” said CSB Team Lead Dan Tillema, P.E. “These workers might have been killed or severely injured, had they not escaped the cloud as the release rate escalated and the cloud ignited, shortly thereafter.”