Investigators believe that blowing dust may have contributed to a major chain-reaction crash involving multiple commercial motor vehicles (CMVs) that left four people dead on Saturday, March 1.

The crash occurred just before 1 p.m. on Interstate 10 near Tonopah, Arizona, under potentially unusual weather conditions.

According to Fox Weather, police reported that the collision involved six tractor-trailers, four passenger vehicles, a van, and an RV towing a trailer. Four people died at the scene, while two others remain in critical condition. An additional six people sustained injuries.

While an official cause has not yet been determined, authorities noted that Dust Storm Warnings were in effect at the time. Investigators suspect that blowing dust may have drastically reduced visibility, contributing to the pileup.

No further details have been released as the investigation continues.