Exxon's Joliet oil refinery reports upset, flaring

Exxon Mobil Corp., the largest U.S. oil company, had an upset that caused flaring at the Joliet, Illinois, refinery, according to a filing with state regulators.

The upset began May 21 before midnight local time and the release of gases was ongoing, the company said in a filing with the Illinois Emergency Management Agency.

Kevin Allexon, a Fairfax, Virginia-based spokesman for Exxon, couldn't immediately be reached by e-mail for comment.

Refinery outages can increase prices for refined products as refiners turn to spot markets to help them meet supply contracts. Operational disruptions can also depress prices for crude oil because less feedstock is needed.

The 248,000-barrel-a-day refinery processes primarily Canadian crude and produces gasoline, diesel, liquefied petroleum gas and asphalt among others, according to the Exxon Mobil.

The Joliet refinery is 42 miles (68 kilometers) southwest of Chicago on the Des Plaines river.