LITTLEROCK, Calif. (KTLA) -- Residents in Littlerock have been allowed to return home after a Union Pacific train carrying hazardous materials derailed, causing concerns of a chemical leak.

The accident happened around 1:25 p.m. Wednesday near the intersection of 92nd Street and Avenue T, prompting the evacuation of some 250 homes.

Twenty-one cargo carrying cars -- out of the train's 62 cars -- derailed, according to the Los Angeles County Fire Department.

The only people aboard the train were its operators, who were not injured.

Fourteen cars were identified as containing hazardous materials.

Fire officials asked residents from 87th Street East to 106th Street East between Avenue S and Avenue T to evacuate as a precaution.

Hazardous materials experts found no signs of a hazardous materials spill, and the evacuation orders were lifted around 3 a.m. Thursday.

The Red Cross set up an evacuation center at Almondale Middle School, located at 9330 East Avenue U.

Authorities began up-righting the train cars early Thursday morning.

Investigators were trying to determine what caused the train to disconnect from the rail.