Sgt. Al Nothum of the Missouri Highway Patrol said backed-up traffic from a tractor-trailer fire a few miles north in south St. Louis County could have contributed to the crash.

In that incident, at Butler Hill Road about noon, the Highway Patrol said a fire in a truck’s brakes spread to the rest of the rig.

The Mehlville Fire Protection District, assisted by other departments, called extra help to the three-alarm blaze at Butler Hill to provide relief to firefighting crews in the extreme heat. The high Thursday was in the mid-90s.

The tractor-trailer was carrying granular chlorine that is used as a water purifier in swimming pools, said Mehlville Fire Chief Brian Hendricks. He said the material can be hazardous in its raw form but the cargo did not pose a significant danger.

An evacuation was not warranted, he said.

"There were no issues that anyone would have to worry about," he said.

No injuries were reported.

The crash at 141 also went to three alarms as firefighters worked in shifts to avoid becoming overheated. “Our guys took quite a beating,” Harder said.