FALLON, Nev. (AP) — A fire Monday at an oil plant in northern Nevada critically injured a 24-year-old refinery worker.

In a statement, Bango Refining said one of its tanks ruptured around 9:15 a.m., sending up a thick plume of black smoke. The company recycles used lubricating oil.

"The plant was operating normally at the time the incident occurred," the company said. "A small fire that resulted from the ruptured tank was quickly extinguished."

Ron Bell, manager at the plant about 60 miles east of Reno, said 14 people were at the site at the time, and one employee who suffered burns was flown to the University of California, Davis, burn center in critical condition.

Churchill County sheriff's deputies said the fire may have happened when workers reportedly tried to thaw a frozen pipe.

State safety regulators confirmed the company has been cited in the past for safety violations.

Records show the Nevada Office of Safety and Health Administration cited Bango Refining in December 2012 for six violations, one involving control of potentially hazardous energy, KRNV-TV reported. Hazardous energy, according to OSHA's website, relates to the "unexpected startup or release of stored energy" that could cause injury to employees during the servicing and maintenance of machines and equipment.

Other violations noted related to exit routes, wiring or components, and guarding floor and wall openings.

In November 2011, OSHA issued a violation regarding procedural steps to control hazardous energy, according to KRNV.

The company Monday suspended operations at the plant pending a full investigation.

"We are grateful to the first responders who airlifted the injured employee to the hospital and to those whose efforts put out the fire," said David Peel, Bango's chief operating officer.