Four people died and 42 others were injured in a series of chain-reaction interstate highway accidents during a blinding dust storm, authorities said. Nearly two dozen vehicles, including a passenger bus and 12 tractor-trailers, were involved in crashes on both sides of Interstate 10 Wednesday evening.

The westbound bus was apparently a charter and belonged to Americano USA, said Officer Norman Jones of the Arizona Department of Public Safety. He said the bus was westbound but he did not know its point of origin or its destination.

There were three separate accidents. Two of them occurred in the Tonopah area, about 45 miles west of Phoenix. The third took place 75 miles west of Phoenix.

"This dust storm came in pretty quick," said DPS Officer Erick Anspach. "Some drivers reported having only a second or two until impact."