A county hazmat team finished its work at a railroad tank car that overheated and leaked a potentially explosive chemical near Perris and the site was turned over to the property owner, fire officials said Sunday.
The Riverside County Fire Department reported that it relieved all personnel that had responded to the chemical spill, which prompted a freeway closure and the evacuation of more than 170 homes and businesses earlier this week.
On Saturday, authorities canceled all evacuation orders after it was determined that the leak did not pose an imminent threat.
The spill at Harvill and Oleander avenues was first reported around 7:30 p.m. Thursday and led to the closure of Interstate 215 south of Van Buren Avenue and north of the Ramona Expressway.
Harvill Road was closed, and evacuations were ordered north of Markham Street, east of Donna Lane, south of Nandina Avenue and west of Patterson Avenue, the fire department reported.
Officials said the insulated train car was holding approximately 138,000 pounds of styrene that had heated up to over 300 degrees, nearly four times the temperature the chemical is supposed to be stored at. It was unclear how much of the chemical leaked out of the train car.
According to the U.S. Centers for Disease Control and Prevention, styrene is used to make latex, synthetic rubber and polystyrene resins. These resins are used to make plastic packaging, disposable cups and containers, insulation and other products.
Authorities were initially worried that the chemical could potentially explode if it were to overheat, and evacuation orders and warnings were issued within a roughly half-mile radius of the leaking rail car.
“This could resolve itself in two days, but it could get worse before it gets better,” Cal Fire Division Chief John Crater said Friday morning. “They’ve also said due to the heat building in the car, that builds pressure and it could have a release, meaning some sort of violent explosion. That’s why we’re taking an abundance of caution with this.”
On Friday, the temperature of the railroad tank car had begun to come down after emergency crews located and used the train’s cooling mechanism. By 11:35 p.m., the unified incident commanders of what was dubbed the Oleander Incident lifted all evacuation warnings and most of the evacuation orders, except for two homes. The I-215 was also reopened in both directions.
All remaining evacuation orders were lifted by 9 a.m. Saturday and fire officials said the evacuation shelter opened at Pinacate Middle School in Perris would be closing.
Metrolink officials said train service remained suspended through Sunday between the Perris South and Downtown Riverside stations and that no alternate service would be provided.
The cause of the leak remains under investigation, though authorities suspect the railroad tank car overheated because of a stabilizing chemical injected into the styrene that failed to work properly.