MALAD, Idaho -

A man was severely burned Thursday night from a propane flash fire.

Oneida County Sheriff's office said the incident happened around 11:30 p.m. at Hess Pumice.

Sheriff JP Semrad reported 3 employees were working a vaporizer that converts liquid propane into vapor.  They had turned everything off, but apparently the regulator had a small leak and propane ignited causing the flash fire.

He said the employees were walking away at the time.  One man received second degree burns on his back and arms.  he was air lifted to the burn center in Salt Lake City.   The other employees were not injured.

Fire officials are still investigating the accident, he said. 

Update:  Earlier it was reported to be an explosion, after further investigation, the sheriff's office determined it to be more of a flash flame, than an explosion.