A large explosion at a West Virginia chemical plant flung debris more than a mile away late on Tuesday night, injuring at least four people and forcing a nearby highway and some schools closed, officials said.
The four people were hospitalized, and officials told residents within a two-mile radius of the blast in the town of Belle, about 15 miles southeast of Charleston, to shelter in place. Classes at more than a dozen schools were canceled on Wednesday as a precaution, a county official said.
The authorities were investigating the cause of the explosion, which apparently involved dry chlorine and methanol, Kent Carper, the Kanawha County Commission president, said early on Wednesday. Firefighters worked to stabilize the blast, which settled into a controlled flare through the night, he said.
“There was a lot of great concern,” he said. “This explosion was so loud that people were describing it, they thought it was an airplane crash or bomb.”
The explosion occurred at about 10:30 p.m. in a manufacturing area owned by Optima Chemicals Co., which operates in a complex in Belle owned by the Chemours Company, Thom Sueta, a Chemours spokesman, said on Wednesday. Emergency responders brought the fire under control by about midnight, he said.
“All Chemours employees were safe and accounted for last night,” he said in an email. “We understand that some Optima employees did sustain injuries.”
“The safety of site employees, emergency responders and the community has been our first priority throughout the incident, so we waited until daylight to begin a thorough site damage assessment,” Mr. Sueta added.
One person was hit by flying debris and drove himself to the hospital, Mr. Carper said, and the three other people had injuries caused either by the fire or the explosion. The company has not released details about the injured people, including whether or how they were connected to the operations there.
Optima Chemical has two manufacturing plants in the United States: the one in Belle, under an agreement with Chemours, and another in Douglas, Ga. The company says it manufactures “high energy and high hazard, sensitive chemistry” on a large scale.
Optima did not immediately reply to a request for comment early on Wednesday. Mr. Sueta said Optima owns the buildings it occupies and the manufacturing equipment in its specific geographic area of the site, and that Chemours has its own manufacturing plant in a different part of the complex.
Mr. Carper, the county commission president, said metal debris was blasted with such force that it was flung hundreds of feet across the river, which is wide enough for barges containing chemicals to pass in two-way traffic.
According to preliminary information, he said, the site of the explosion was on a river bank. “Obviously some form of apparatus exploded, and blew metal,” he said. The shrapnel fragments were “very large in some cases. They hit cars, they blew clear across the river, hundreds of feet from the explosion, one city to another.”
He said fire officials smelled chlorine when they arrived at the site, which stretches across more than 700 acres.
Several companies are involved in the operations and management at the site, he said. “It took place within the fence,” he said.
Concern about the explosion, Mr. Carper said, “shut down the entire education system in that part of the county. All together, 13 schools were closed.” About 20,000 people were affected by the shelter-in-place orders and Route 60, an interstate, was closed for several hours, he said.