By Steve Robrahn
LOUISVILLE, Ky (Reuters) - Firefighters were letting a chemical plant fire burn itself out on Tuesday after an explosion killed two workers and injured two others.
The fatal explosion, involving calcium carbide, occurred Monday evening at the Carbide Industries plant in Louisville's Rubbertown district, a heavily industrial area with 10 other chemical plants near the Ohio River, authorities said.
A second explosion, which fire officials said involved mineral oil, rocked the site nearly five hours later but no one was reported injured. The plant uses calcium carbide to produce Acetylene gas among other products, according to a company website.
The dead were Steven Nichols, 59, of Charlestown, Ind. and Jorge Medina, 56, of Louisville, said Deputy Jefferson County Coroner Jack Arnold. The others were treated and released at University of Louisville Hospital.
Louisville Metro Police issued a hazardous chemical warning for the area but health officials said nearby residents had not been at risk. Mayor Greg Fisher announced an investigation Tuesday into coordination problems between police and MetroSafe, the local emergency management agency.
(Editing by Greg McCune)