A shelter in place remains in effect Friday following a train derailment, town officials said.

Local officials provided an update at a noon press conference and advised residents to keep windows shut and remain sheltered as a precaution.

Mansfield Fire Chief John Roache said crews are still working at the derailment site after a train left the tracks Thursday morning.

Roache said the cleanup effort is slowed by cold weather, but warming tents have been set up for workers.

The train was carrying grease and liquid propane, and four propane tank cars went into the Willimantic River, Roache said. None of the tanks are leaking.

Crews placed several booms downriver overnight as an added safety measure in case of a spill, he said.

Roache said people should continue to avoid the area because of increased traffic from cleanup operations.

Officials said 13 of the train’s 43 cars became detached. Ten of those cars derailed near Route 32 in Mansfield.

One worker suffered a minor head injury after slipping and falling, officials said.

The rail company brought in heavy equipment overnight, including cranes and excavators.

Officials said rail shipments are not impacted because trains can be rerouted. The cause of the derailment has not been determined