In Southern California, contents of rail cars are not classified as an 'immediate threat' after 100 homes were evacuated due to a chemical leak

Due to a chemical leak from a railroad tank car, authorities in Southern California had to temporarily close a major highway and evacuate more than 100 homes on Friday for fear of an explosion.

Late Friday evening, officials determined that the contents of the wagon posed “no immediate danger” to Highway 215 and reopened the highway. According to a Twitter statement from Cal Fire and the Riverside County Fire Department.

Evacuation warnings and orders have been lifted for most of the area, except for the area west of the highway, where an evacuation order remains in effect, the statement said.

Officials had previously said the train car was leaking a chemical called styrene, which is used to make plastic products. Styrene is a highly flammable substance that can cause skin and eye irritation and is toxic if inhaled, according to the National Institutes of Health. One of the main concerns was that the train car could explode as pressure builds inside the train car and temperatures rise throughout the day.

The railroad car was parked on a track that runs parallel to Highway 215, near businesses and a residential area north of Perris, California, 75 miles inland from Los Angeles. Styrene is normally stored at about 30 degrees, but the temperature inside the container reached at least 160 degrees, officials said.

“This hasn't happened in a long time and it's rare,” said John Crater, division chief of Cal Fire Riverside County, at a press conference early Friday. “So we're in uncharted territory.”

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It is unclear what caused the leak. Officials admitted at the press conference that they were not familiar enough with how to handle the substance.

Crater said he spent the night on the phone with experts from other states who told him the leak could repair itself in two or three days.

Riverside County Fire Department Captain Oscar Torres described the substance as “resin” at a news conference Friday and said officials did not expect an explosion as powerful as that caused by a propane tanker.

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Fire department responded to the leak on Thursday at 7:41 p.m. and closed the Autobahn 215. They set up a Evacuation zone early Friday just before 1 a.m. and people were evacuated from about 170 houses.

Authorities issued an evacuation warning for another 928 homes in the area later in the day, according to Jeff LaRusso, spokesman for the county fire department.

A local middle school said the Red Cross was operating an evacuation and care center in its gymnasium.

This article originally appeared on USA TODAY: Southern California chemical leak: Evacuations lifted in Riverside County