PITTSBURG COUNTY, Oklahoma - Officials are investigating what caused a train derailment in Pittsburg County.

Crews spent hours working to clean up the mess after 16 Union Pacific Rail cars and one locomotive derailed early Sunday morning along Highway 69 south of McAlester.

Officials with Union Pacific say, just after 6:30 a.m. the train derailed going northbound, two miles north of Kiowa.

 There were no injuries and most of the cars were empty so there were no hazardous material involved, officials said.

The derailment happened near a railroad crossing and the pile up blocked off a private road.

Oklahoma Highway Patrol closed one southbound lane of Highway 69 while crews worked on the scene. 

The closure caused slow traffic in the area down for most of the day.

 After investigating the crash all morning, crews showed up with heavy duty equipment to haul away each of the rail cars. One of the rail cars was loaded with heavy coils that had to be removed before crews could haul away the rail car.

Union Pacific says they apologize for any inconvenience this causes the community.

Right now the cause of the derailment is still under investigation.