Authorities said a pressure release valve on the car was leaking styrene, a toxic and flammable chemical that is used to make plastic and rubber. It can cause headaches, nausea and respiratory issues, and long-term exposure can lead to more serious health problems including organ damage.
Aerial video showed firefighters spraying down the car, which was sitting upright on tracks between a highway and an asphalt plant.
Crews were working to “cool the tank to maintain the temperature,” said Chief Mike Siefke of the Little Miami Joint Fire and Rescue District at a news conference Tuesday evening. Initially, officials were concerned the railcar’s rising temperature could lead to an explosion, but Siefke said that is “not a concern we have right now.”
The leak has stopped and the impacted car has been removed from other railcars, said Brian Stussie, assistant vice president of operations at Genesee & Wyoming railroads.
Air quality testing was ongoing Tuesday evening, with results expected Wednesday morning, officials said. No injuries have been reported.
Hamilton County’s Emergency Management Agency advised anyone within a half-mile of the area near US Route 50 and the Great Miami River, west of Cincinnati, to leave immediately. About 200 homes are in the evacuation area, Siefke said. Residents just outside the evacuation area were told to stay inside and keep their windows closed.
The area has a mix of businesses, homes and large swaths of undeveloped land.
“To our knowledge, all residents that have been displaced have been taken care of,” said Andrew Knapp, director of the Hamilton County 911 Center.
Three school buildings were evacuated and all after school events were canceled, said Lisa Whiteley, a spokesperson for the Three Rivers Local School District.
“This is going to be a long event. It’s not going to be short,” Siefke said, asking for the community’s patience during the cleanup effort.
Tom Ciuba, a spokesperson for Central Railroad of Indiana, said it was notified Tuesday afternoon about a railcar near Cleves that was venting styrene. He said firefighters were at the site and environmental response agencies were mobilized.
US Transportation Secretary Pete Buttigieg said personnel from the Federal Railroad Administration are headed to the area to assist as needed.
Last year a train derailment on the opposite side of Ohio in East Palestine, about 300 miles northeast of Cincinnati, caused hazardous chemicals to leak and burn for days. The February 2023 derailment near the Ohio-Pennsylvania state line led to new safety rules and increased scrutiny of the rail industry and federal regulators.
CNN’s Melissa Alonso contributed to this report.