Hundreds of St. Louis residents fled a five-alarm fire that broke out after tanks caught fire at a chemical plant in the early hours Monday, NBC affiliate KSDK reported.
The fire started at Chemisphere Corp. at around 2:30 a.m., KSDL reported. The area reportedly contains some 30 chemical tanks and a building full of alcohol-based solvents.
"We had a tremendous amount of solvents involved," St. Louis Fire Chief Dennis Jenkerson told reporters at the scene, KSDK reported.
Firefighters battled the blaze, which caused the closure of part of Interstate 44 and forced some 500 residents from their homes, into the morning, according to KSDL.
The residents, who lived within three blocks of the plant, returned home at around 7:30 a.m., according to KSDL.
Four railroad cars carrying a kind of solvent and seven tractor-trailers were involved in the fire, Jenkerson told reporters.
"We've got it under control," he said.
Experts were on the scene evaluating air quality, he told reporters.
Three firefighters were taken to a nearby hospital after being injured in an explosion, the station reported.