ST. LOUIS — A section of the Mississippi River was shut down in northeast Missouri on Tuesday after a cloud of sulfur trioxide gas was released from an industrial plant. The BASF plant and others nearby were evacuated.
No injuries were reported, and officials from the Missouri Department of Natural Resources were trying to determine how much of the gas was released at the plant, which is between Hannibal and Palmyra, about 115 miles north of St. Louis.
When mixed with water, sulfur trioxide becomes sulfuric acid, which can cause serious health problems and even death if ingested or inhaled. The DNR sent an emergency environmental responder to the site to determine the possible ramifications for humans, animals and the environment.
"About 8 o'clock, BASF had what appeared to be a failure of a mechanical system in one of its stacks," DNR spokesman Judd Slivka said. The agency said the gas release continued through midmorning.
BASF did not immediately return a phone message seeking comment.
The plant, which makes chemicals for the agricultural industry, and neighboring industries were evacuated, but DNR officials were not aware of any residents being evacuated. The U.S. Coast Guard closed a seven-mile stretch of the Mississippi River to all traffic.
The gas cloud was blowing into Illinois. The section of Illinois closest to the plant is sparsely populated, but there was some concern that the plume of gas could make its way to Quincy, a town of 40,000 about seven miles northeast of the plant.
Dennis McMurray, a spokesman for the Illinois Environmental Protection Agency, said he was not aware of any evacuations on the Illinois side of the river. An official with the Adams County, Ill., emergency management office did not return messages seeking comment from The Associated Press but told KHQA-TV there was no threat to Quincy and no plans to evacuate anyone.
Germany-based BASF SE's Web site says it is the world's largest chemical company, with about 97,000 employees worldwide.