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CSB to investigation release at Exxon Mobil's Joliet, Ill., refinery

The US Chemical Safety Board sent an investigative team to Exxon Mobil Corp.’s Joliet, Ill., refinery on Aug. 7 following a propane and hydrogen fluoride release there a day earlier. It was the third HF release CSB has investigated this year, CSB Chairman John S. Bresland said.

“We are concerned about the three apparent releases of hydrogen fluoride from refinery alkylation units in Pennsylvania, Texas, and now Illinois that have been reported since March 2009. Because of its high toxicity, any loss of primary containment for hydrogen fluoride is a serious matter,” he said.

CSB has investigators examining a July 19 HF release at Citgo Petroleum Corp.’s Corpus Christi refinery. It said that a similar incident occurred on March 9 at Sunoco Inc.’s Philadelphia refinery.

The Aug. 6 incident at Exxon Mobil’s 238,600 bbl a day Joliet plant occurred around 12:30 p.m. CDT when HF and propane suddenly leaked from the refinery’s alkylation unit, which uses HF as a catalyst, according to CSB.

It said that the leak did not ignite, but one operator was transported to the hospital suffering from what were described as serious, HF-related chemical burns, and was initially reported in critical condition. A second operator was examined at the hospital and released, it said.

CSB said that the unit’s water deluge system, which is designed to contain airborne HF releases, was activated and the alkylation unit was shut down as refinery employees sought shelter.

Investigation supervisor Robert Hall leads the team, CSB said.

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