Multiple people are dead after a tanker carrying anhydrous ammonia crashed and rolled over Friday night in Effingham County, Illinois.

Around 5 p.m. local time, a crash on Interstate 70 caused traffic to be rerouted to U.S. Highway 40.

Then around 9:30 p.m. on U.S. Highway 40, about a half-mile east of Teutopolis, Illinois, a second crash was reported, according to the Illinois State Police. Multiple vehicles were involved and a truck hauling anhydrous ammonia began leaking after rolling over.

Due to the plume from the leak, officials evacuated residents within a 1-mile radius. 

Crews are still on scene Saturday afternoon and working to contain the leak while first responders and emergency workers continue to respond to the incident, state police said.

Authorities have not confirmed the number of fatalities, but The New York Times on Saturday reported that at least five people died. It was not immediately clear whether the deaths were related directly to the crash or to the resulting ammonia leak.

In a statement Saturday, the National Transportation Safety Board said it will be investigating the incident and is sending a 15-person team to the scene; that team was expected to arrive Saturday evening.