By Kyle Potter and Archie Ingersoll / Forum News Service

CASSELTON - The voluntary evacuation of Casselton after the fiery train crash nearby is being lifted at 3 p.m. today. Multiple health and environmental officials say the air quality is now safe for residents to return. Hazardous materials crews from Burlington Northern Santa Fe will still be working to clear the wreckage and extinguish any smoldering fires from the burning railcars, said a news release from the Cass County Sheriff's Office.. There may be small flare ups or smoke clouds as cars are being moved. In these instances residents should keep a respectful distance. Current predictions are that winds are favorable for the city of Casselton from the North/Northeast direction. Those directly within one mile south of the incident location are being advised to use extra caution upon returning to their homes. Gov. Jack Dalrymple called Monday’s collision and fire in Casselton, his hometown, a “huge accident” that could have been far worse. Dalrymple is set to visit the site of the crash this afternoon, where he will meet with local officials and federal investigators from the National Transportation Safety Board to discuss accident response, safety and what may have caused the crash. Robert Sumwalt, an NTSB board member, offered an official summary of the crash between the two BNSF freight trains: About 2:10 p.m., a westbound train carrying grain derailed near Casselton. Cars from that train went onto the adjacent track, and an eastbound train hauling crude oil struck those derailed cars. The two locomotives pulling the oil cars were destroyed in the crash. Twenty cars from the eastbound train derailed; 19 held oil and one was a sand-filled car used as a safety buffer between the locomotives and the oil cars. More than 10 of those oil cars eventually caught fire and exploded, belching a thick cloud of black smoke into the air that led local and county officials to urge the 2,400 citizens of Casselton about 20 miles west of Fargo to evacuate. In an interview, Dalrymple said he plans to ask the NTSB whether anything could have been done to prevent the crash. He said it’s currently unclear how long the first train was derailed before it was struck. “It’s a huge accident, I don’t think there’s any denying that,” the governor said. “There are a lot of questions, and I suppose the first one is: How did this train derail in the first place?” Dalrymple also acknowledged the accident may stir anxiety among North Dakotans, who may not have given second thought to hundreds of trains carrying oil through their towns. But he stressed that Monday’s crash was a "bad coincidence."