Industry was warned for years about chemical 'runaway' dangers. Then came near-catastrophe in O.C.

Thermal runaway incidents in the chemical industry have long been recognized as serious hazards. Nearly 15% of U.S. incidents involving uncontrolled chemical reactions from 1980 to 2001 involved thermal runaway, including rapid polymerization. Such events have caused deaths worldwide, and some experts say safety improvements have been insufficient. In Orange County, a crisis was triggered by thousands of gallons of methyl methacrylate in a failing pressurized tank at a Garden Grove aerospace firm. Authorities suspect the tank’s cooling system failed, allowing heat to build up. The heated chemical off-gassed through a relief valve, prompting a response that could have included fire or flash fire across city blocks, with businesses, homes, and an elementary school in a potential blast zone. The worst-case outcome was avoided, but questions remain about how the near-disaster occurred.

"Nearly 15% of incidents in the U.S. involving uncontrolled chemical reactions between 1980 to 2001 were thermal runaway incidents that involved rapid polymerization of a chemical, according to a study published in the journal ACS Omega, citing information from the U.S. Chemical Safety and Hazard Investigation Board."

"In Orange County, the crisis was sparked by thousands of gallons of a highly toxic chemical in a failing pressurized chemical tank that was heating up at a Garden Grove aerospace firm. There was a potential of fire or flash fire over many city blocks, and there were businesses, dozens of homes and an elementary school in a potential damage blast zone."

"Authorities suspect that the cooling system responsible for maintaining the temperature of a tank filled with a hazardous chemical at GKN Aerospace failed, leading to the crisis at the facility that triggered evacuations, Orange County Fire Authority Interim Chief TJ McGovern said Tuesday."

"This likely led to a buildup of heat in the pressurized tank filled with 7,000 gallons of a highly reactive liquid chemical called methyl methacrylate, or MMA, which can be used to make items such as Plexiglass as well as household goods. "We don't know why, but it stopped cooling," McGovern said Tuesday. "So that's what started this event, to where the product heated up and it off-gassed through the relief valve, and that's how this whole response started.""

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