(CNN) – Union Pacific technicians are preparing to remove the cars after a train derailment and fire that triggered evacuations in northwest Iowa on Sunday, Union Pacific spokesman Robynn Tysver said Monday.
“We know that the impacted cars were carrying hydrochloric acid, potassium hydroxide and asphalt,” Tysver said in an email to CNN.
The train derailment occurred around 2 pm Sunday in Sibley, Iowa. It is estimated to have affected 47 cars, Tysver told CNN affiliate KMEG. There were no injuries to the train’s crew, Tysver added.
Voluntary evacuation orders remain in effect. In addition, the Sibley-Ocheyedan Community School District is operating a delayed entry time, the district stated in a Facebook post.
The cause of the derailment is under investigation, Tysver said. The authorities indicated that the fire was caused by diesel, according to KTIV, a CNN affiliate, and that the derailment was caused by the collapse of a bridge.
For people who did not evacuate, the Osceola County Sheriff’s Office wrote in a facebook post in which “residents are advised to open the windows on both sides of their houses and stand in the center of them.”
“This is a safety measure in case a car explodes,” wrote the sheriff’s office.
Waterways in the area are blocked, KTIV reported.
CNN contacted the sheriff’s office and county emergency management for more information.