Feds to probe leak at Exxon's refinery

A federal agency will investigate at Exxon Mobil Corp.'s Joliet refinery in Illinois after two workers were hospitalized and an alkylation unit was shut due to a leak.

"There's not a lot of detail" yet on the incident, said Robert Hall, a chief investigator for the U.S. Chemical Safety Board, who said he will inspect the refinery next week.

The investigation is the second involving a refinery's alkylation unit in less than a month for the federal agency, which investigates chemical accidents.

The leak in the depropanization unit associated with the alkylation unit had trace amounts of hydrofluoric acid, Tricia Simpson, a spokeswoman for Exxon, said in a telephone interview.

One of the two workers remains hospitalized and the other was released following "precautionary treatment," Simpson said.

An alkylation unit produces a high-octane additive that can be blended with motor and aviation fuel. Hydrofluoric acid, which can be used in the unit, is corrosive and toxic.

They are "working on the alkylation unit," Simpson said, declining to estimate when it will be completed.

The refinery has a capacity of 240,000 barrels a day, according to data compiled by Bloomberg.

The U.S. Chemical Safety Board is also investigating a July 19 fire that broke out at an alkylation unit at Citgo Petroleum Corp.'s 165,000 barrel-a-day Corpus Christi, Texas, refinery. The incident left worker Gabriel Alvarado, 34, in critical condition.