PERRIS, Calif. (AP) — Remaining evacuations orders for a Southern California neighborhood were lifted Saturday after authorities cooled down a railroad tank car filled with an overheated chemical they had feared could explode.
No injuries were reported in the situation that began Thursday night in Riverside County, east of Los Angeles, when a tank car filled with styrene emitted a plume and authorities discovered the substance was very hot and building pressure.
Adjacent Interstate 215 was shut down and authorities issued evacuation orders for a half-mile radius (0.8 kilometer), including 170 residences as well as businesses.
The temperature of the styrene, used to make foam products, reached 323 degrees (161.1 Celsius) before beginning to trend downward early Friday.
But the tanker was still considered too dangerous to approach so drones were used to monitor it, according to officials of the California Department of Forestry and Fire Protection / Riverside County Fire Department.
Authorities waited until night when the sun's heat was no longer coming down on the tank car, fire official Mark Scoville told KTLA-TV Saturday morning.
“We were able to get people in to do an inspection of the tank which then gave us the OK to go ahead and start cooling,” he said.
The tank has heating coils that were effectively reversed to become cooling coils.
The interstate was reopened and evacuations on the east side of the freeway were lifted just before midnight Friday. Evacuations were lifted on the west side Saturday morning.
Authorities believe the heating reaction began after a stabilizing chemical in the tank broke down over time.