Sixty people who had to leave their homes after a train derailment pumped toxic fumes into the air earlier this week were allowed to return on Friday.

Hazardous material crews had neutralized and removed most of the soil contaminated when a 65-car train derailed and spilled toxic phosphoric and hydrochloric acid on Monday near the community 140 miles southeast of Los Angeles, Riverside County fire Capt. Fernando Herrera said.

Air quality readings indicated no hazardous vapors.

Herrera said a five-mile stretch of Highway 111, plus some roads, would remain closed until the cleanup was fully complete.

Union Pacific opened up the railway Friday morning after conducting a stability check on the tracks.

The cause of the accident was under investigation.