Eight cars on the 110-car Burlington Northern Santa Fe train derailed, seven of which were carrying either crude oil or ethanol, company spokesman Joe Faust said. He said he didn't know how many of the derailed cars had caught on fire.
He said only two people - an engineer and a conductor - were aboard the train, and neither was injured.
The derailment occurred around 3 p.m., about 30 miles northeast of Oklahoma City, close to the town of Luther. The train was traveling less than 40 mph from Tulsa to Temple, Texas, on tracks operated by Stillwater Central Railroad. A call to the railroad's office went unanswered Friday afternoon.
Television footage showed intense flames and heavy black smoke in the rural area. CBS affiliate KWTV reported that several fire crews arrived on the scene but could not get near the fire because of the danger, according to Cecil Clay, Oklahoma City deputy fire chief.
The railroad tracks near the site of the fire appeared to be bent, and an oil pump jack was located nearby.
Explosions at the site sent large balls of fire into the air, and the blaze continued into the evening. Edmond Fire Department spokesman Tim Wheeler said firefighters from five different towns initially responded, although some later were sent home as the blaze subsided somewhat.
With only small areas still burning, BNSF's hazardous materials crews applied a flame-retardant foam to suppress lingering flames, Faust said. By 8 p.m., the fire was under control and the command center disbanded, he said.
Crews from BNSF and investigators from the Federal Railroad Administration were en route to the scene Friday, said Faust and Federal Railroad Administration spokesman Steve Kulm.
Oklahoma County Sheriff's Department spokesman Mark Myers said authorities blocked off a one-mile-radius area around the fire.