2012-06 Chemical spill at ConocoPhillips in Rodeo

2012-06-15 "Rodeo refinery spill prompts Benicia alert"
by Donna Beth Weilenman from "Benicia Herald" [http://beniciaherald.me/2012/06/15/rodeo-refinery-spill-prompts-benicia-alert/#more-18106]:
A strong odor in Benicia caused by a spill at a Rodeo-based refinery prompted a communitywide alert Friday morning, though Fire Chief Steve Vucurevich said no shelter-in-place warning was required.
The city’s dispatchers handled more than 300 calls from residents who were worried about the smell, and of those, 30 were directed to the fire department, Vucurevich said. “It was definitely a strong odor.”
The ConocoPhillips refinery, 1380 San Pablo Ave., experienced the release about 7:45 a.m. It was handled by Contra Costa Fire Protection District, according to information Vucurevich and the city alert system provided.
Contra Costa Environmental Health was told of the spill, the notification said.
Vucurevich said he learned from Colby LaPlace, Solano County Department of Resource Management specialist, that the ConocoPhillips refinery experienced overpressurizing in a sour water tank, causing it to leak.
“That’s what is causing the odor,” he said.
The smell, which residents said was like rotten eggs, was from hydrogen sulfide contamination in the tank’s water. Prevailing winds were expected to dissipate the odor, residents were told.
“They’re putting foam on it to reduce the vapors and odor, and they hope it will be mitigated by 4 p.m. today,” Vucurevich said Friday.
Contamination near the Contra Costa County refinery reached 1 part per million, said Randy Sawyer, Contra Costa County chief environmental health and hazardous materials officer.
The gas becomes a hazard at 30 parts per million, but the odor becomes more offensive long before it reaches that level, Sawyer said.
He explained that the smell might make some motorists in the vicinity of the ConocoPhillips refinery might feel nauseated if heavy traffic slowed their driving times.
Valero Benicia Refinery employees checked the refinery’s ground level monitors’ measurements, and were able to to provide information to local officials, Vucurevich said.
Based on the data provided by the local refinery, which otherwise was not involved with the spill, the city authorized the notice to the public, but learned it did not need to issue a shelter-in-place warning or sound alarms.
“We activated the CAN (community alert network) system to get the information out to the community,” Vucurevich said. “It’s not a health risk to us.”