"As it relates to the public safety concerns, we are still maintaining a half-mile evacuation zone. Additionally, the roads that are closed will remain closed for an undetermined amount of time," Little Miami Fire and Rescue Chief Mike Siefke said during a press conference on Wednesday.
Following the incident, Siefke told reporters that there was "potential for an explosion" at the site of the leak.
Central Railroad of Indiana officials John Keefer and Tom Chuba told reporters at the press conference that air and water quality in the area are still being monitored to ensure safety.
According to local authorities, the leak has not resulted from a train derailment, but from a problem with a car valve.
The White House said in a press release on Wednesday that President Joe Biden has been briefed on the styrene leak and has directed his team to provide any resources that may be needed.