PERRIS, Calif. (AP) — A Southern California freeway was shut down and nearby homes were under evacuation orders Friday as a chemical reaction inside a railroad tank car threatened to cause an explosion, authorities said.
The tank car was parked on a spur off a main rail line along Interstate 215 in Riverside County, about 57 miles (92 kilometers) east of Los Angeles.
The evacuation zone extended a half-mile (0.8 kilometers) in all directions and included 170 residences. The area has a mix of businesses and large plots of undeveloped land between the city of Perris and March Air Reserve Base.
County fire officials identified the chemical as styrene, which is used in making foam products.
John Crater, a fire division chief, said in a briefing that it was too dangerous to get close to the tank car and that officials were observing it with drones. Experts advised that it could take two to three days for the situation to be resolved, he said.
The problem was discovered when a plume was seen coming from the rail car at about 7:40 p.m. Thursday. Authorities said the plume spread over Perris before dissipating.
Authorities said the chemical's normal temperature is 85 degrees (29.4 Celsius) and the tank's temperature had reached 323 degrees (161.6 Celsius) before declining to 304 degrees (151.1 Celsius) Friday morning.