(Reuters) - Marathon Petroleum (NYSE:MPC) said on Thursday four employees were transported to local medical facilities for evaluation after they were exposed to a release at its refinery in Wilmington, California.
The Los Angeles Fire Department (LAFD) said the reported leak of butane and hydrogen sulfide gases had been shut down and the risk of hazardous materials mitigated.
At least three people were overcome by gas fumes, said sources familiar with plant operations.
One of the four patients was in serious condition, while the others were listed as 'moderate' by the LAFD, which added that one was "rescued by a rigid basket/stretcher and lowered by a rope system to ground level."
Marathon's Los Angeles refinery includes the Wilmington and Carson refining units that have a joint capacity of 363,000 barrels per day.
The Los Angeles plant manufactures California Air Resources Board (CARB) gasoline and CARB diesel, conventional gasoline, distillates, petroleum coke, anode-grade coke, chemical-grade propylene, fuel-grade coke, heavy fuel oil and propane, according to the refinery website.