(CASSELTON, N.D.) -- Officials are urging residents of a small North Dakota town to evacuate after a mile-long train carrying crude oil collided with another train, triggering a series of thunderous explosions and sending toxic fumes into the air.
About 2,400 people live in Casselton, a mile from Monday's fiery derailment. The Cass County Sheriff's Office is "strongly recommending" an evacuation of the city of Casselton and anyone residing five miles to the south and east of the town.
The main concern for residents' safety is related to the fumes from the fire, Cass County Sheriff's spokeswoman Sgt. Tara Morris said. There's a high-pressure system coming in that is expected to push the plume of smoke into town.
Cass County Sheriff Paul Laney said, "Our job right now is to protect the citizens of Casselton and the surrounding area and that's what we intend to do."
About 65 percent of residents had evacuated the area as of Monday night, according to the Cass County Sheriff's Office.
People who have respiratory conditions such as asthma, emphysema or bronchitis are urged to stay inside if they have not already evacuated.
"Crude oil, as it burns, has a lot of particulate matter in it, lot of fumes and other bad things that are really bad for people, especially those with respiratory illnesses," Dr. John Baird of Fargo-Cass Public Health said.
No injuries have been reported.
Authorities will let the fires burn, hoping some of the oil will burn off and make the job for firefighters easier Tuesday morning, Morris said.
Officials don't expect any more explosions even though 18 cars were still burning Tuesday as of 1:30 a.m. ET, she added.
Authorities have not yet been able to untangle what exactly caused the derailment, but an investigation is underway. A train carrying grain derailed first, and then knocked several cars of its crude oil train off adjoining tracks, BNSF Railway Co. spokeswoman Amy McBeth said.
Video taken three quarters of a mile away captured the moment one of the train cars exploded. A mushroom cloud of fire blasted into the sky and then black smoke smothered the surrounding area as the wreckage continued to burn. The flames created dark clouds that could be seen for 15 miles.
"It was almost like nighttime," eyewitness Loren Parks said. "It was just dark. The entire sky is just blacked out, you can't see anything."
There were 112 cars in the westbound grain train and 106 cars in the eastbound crude oil train, according to BNSF. The majority of train cars were not derailed and pulled away from the derailment location.
Only 20 people have gathered at a middle school in Fargo, which has been turned into a shelter, Morris said. Evacuations for residents of Casselton will remain voluntary, she added.
This explosion is the third accident in the past six months involving trains transporting North Dakota crude oil. No injuries or deaths were reported when a 90-car train derailed in rural Alabama in November, but the aftermath is still being cleaned up.
In July, an oil train derailment in Quebec killed nearly 50 people.
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