Corrosion may have caused the pipe failure that ignited Monday's massive fire at the Chevron refinery in Richmond. The preliminary finding comes from the federal agency investigating the fire.
It's still not safe enough for investigators to get close to the failed pipe, but now there are more questions about the pipe's history and stability.
The U.S. Chemical Safety and Hazard Investigation Board, or CSB, is calling Monday's fire among the most serious U.S. refinery incidents in recent years. Federal inspectors believe a corroded pipe may have played a role in the fire.
In November 2011, Chevron conducted its own maintenance inspection on the line that failed and on an adjacent, connector pipe. At the time, Chevron replaced only the connector line because of corrosion.
"Corrosion is certainly one of the possible failure mechanisms and in light of the other pipe, it's certainly one that we will be looking at," said CSB director Daniel Horowitz.
The fire broke out in the Number 4 crude oil unit. Thick black smoke filled the sky above Richmond. Thousands rushed to area hospitals, complaining of blurred vision and breathing problems. And now, the federal agency has learned Chevron workers were engulfed by a vapor cloud.
"That vapor cloud, when it ignited, could easily have caused deaths or serious injuries. So that's a serious concern here," said Horowitz.
Chevron meantime, had very little to say about the CSB's report.
"This is part of an ongoing investigation and for us to comment on this report or these reports coming out today are premature. The facts will bear themselves out through the process," said Chevron's media advisor Justin Higgs.
Federal inspectors have already asked Chevron for last year's inspection records and they hope to begin testing the failed pipe next week. Meantime, Richmond city leaders and residents want to know more about the failed pipe and the possibility of corrosion.
"I know that accidents will happen, even in a well-run facility. I'm OK with that, but I just have a zero tolerance policy if there is any cutting corners, any slipshot work," said Richmond City Councilmember Jim Rogers.
"Why would that pipe corrode like that? How could that not be monitored?" said Richmond resident Ruby Gonzales.
By not replacing the pipe in question last year, investigators say that Chevron assumed it was strong enough to last another five years, which is when the next inspection would have taken place.