Contra Costa County health officials say they're satisfied so far with Dow Chemical Co.'s response to a recent chemical release at its Pittsburg plant, and hope to form a more complete picture later this month of what happened and why.
The company presented its preliminary report on the March 27 incident to the county this week, the same day that a crew of expert internal investigators began work on determining a root cause of the accident.
Dow Chemical spokesman John Kneibel says a team of Dow specialists from around the country hopes to figure out what led to the 2:50 a.m. release of thousands of pounds of chemicals into the air, and what it can do to prevent such problems in the future.
"This is not something that happens very often, even with Dow Chemical Company Global, so we're going to take a very close look and see what things may have caused this," Kneibel says.
Country Costa County Chief Environmental Health and Hazardous Materials Officer Randy Sawyer says the company alerted the proper parties and responded quickly to the incident.
At issue is a tank used as a combination reactor and dryer in the processing of antimicrobial chemicals. Sawyer says the tank normally evaporates methylene chloride, condenses it and cycles it back into the tank, which helps keep the reaction cool. He says Dow believes the line back into the tank may have become plugged.
Dow employees were in the process of adding 1,000 gallons of methylene chloride from another vessel to try to cool off the reactor when it overheated and triggered the release.
"I think they were surprised that temperature and pressure went up as fast as it did," Sawyer says. "They seem just as interested as we are in finding out what happened, why the line plugged and things heated up so quickly, or if something else led to this problem."
While the county issued a brief health advisory for Pittsburg and Antioch, no injuries were reported and there is no evidence that the chemicals landed anywhere other than back onto the Dow plant property.
"It was a liquid release that went straight up and straight back down," Sawyer says. "The chemicals did not aerosolize. There was very little wind that night, and the closest homes downwind were over a mile away, so the likelihood that anyone would even have known about this or be impacted is very, very remote."
The company is required to submit its final report to the county this month.