At least 37 people were killed and 150 others injured Sunday night, Sept. 9, in northern Mexico when a truck loaded with 25 tons of dynamite caught fire and exploded after colliding with a van.

According to CNN, the explosion occurred at a factory about 125 miles northwest of Monterey, and the dynamite didn’t explode until about 40 minutes after the crash.

By that time, a large group of soldiers, emergency workers, reporters and nearby residents had gathered around the crash site, CNN reported.

Media reports haven’t given specific information on the truck driver, whether he or she tried to warn anyone, or whether the trailer was hazmat placarded to indicate there were explosives inside.