Two dead in Indiana plant explosion -company

(Updates with contract workers' company statement)

HOUSTON, April 28 (Reuters) - Two contract workers were killed in an explosion at a West Terre Haute, Indiana, petroleum coke gasification plant on Monday morning, one of the plant's owners said in a statement.

The accident occurred "when a flanged opening on a high pressure vessel containing synthetic gas failed," according to a statement issued by Wabash Valley Power, a 50-percent owner of SG Solutions, which operates the plant.

The contract workers killed were employees of Sterling Boiler and Mechanical Inc, headquartered in Evansville, Indiana, according to a statement from that company.

Firefighters from the Sugar Creek, Indiana, Fire Department were called to the plant shortly before 11 a.m. EDT (1500 GMT), said Fire Chief James Holbert.

"They had some type of vessel failure up there," Holbert said. "There were some injuries."

Local media reported the explosion in southwest Indiana rattled windows several miles away. (Reporting by Erwin Seba and Andrew Stern in Chicago; editing by Gunna Dickson)