EFFINGHAM COUNTY — Transportation officials say a fatal tanker truck crash in Effingham County that released a deadly chemical may have started when another vehicle tried to pass the truck on a highway.

According to the National Transportation Safety Board, the truck ran off the road after pulling to the right. It jackknifed, toppled over and hit a utility trailer parked by the side of the road.

The crash Friday night killed five people, and injured five others.

Those killed were 34-year-old Kenneth Bryan of Teutopolis and his two children, seven-year-old Rosie Bryan and 10-year-old Walker Bryan, both from Beecher City.

The other two killed were 67-year-old Danny J. Smith of New Haven, Missouri, and 31-year-old Vasile Cricovan of Twinsburg, Ohio. All five of those killed died due to inhalation of the anhydrous and not due to injuries from the crash.

Due to the plume from the ammonia leak, roughly 500 residents were evacuated from northeastern parts of Teutopolis and U.S. Highway 40 was closed between Effingham and Montrose.

They were eventually allowed to return.