The New Mexico Environment Department says it’s reached a settlement with Navajo Refining of Artesia for citations issued by the Department’s Occupational Health and Safety Bureau, or New Mexico OSHA. The citations resulted from an investigation of a March 2010 accident, which killed two employees and seriously injured two others at the Artesia refinery.

As part of the agreement, the company will pay a $400,000 fine, the highest penalty ever collected by the state OSHA program. The company does not admit fault.

The accident occurred when employees of Northwest Insulation of Texas were performing welding operations on top of a storage tank at the refinery. The four victims, all Northwest employees, had just finished lunch on March 2, 2010. When the crew resumed work after the lunch break a welder ignited vapors from flammable liquids within the tank. The resulting explosion ripped open the top of the tank and the ensuing fire burned for more than an hour before being extinguished by the refinery’s fire brigade.

“The hazards of welding on or near petroleum storage tanks, as well as methods for preventing associated accidents, are well known within the industry,” said Robert Genoway, Acting Bureau Chief for New Mexico OSHA. “This type of hazard has resulted in far too many inexcusable accidents and deaths in New Mexico and nationwide.”

New Mexico OSHA cited both Navajo Refining and Northwest Insulation for violations which included failing to properly inspect the work area prior to welding, failing to instruct employees on methods for determining the presence of flammables, and permitting the employees to weld in an area where flammable liquids and vapors were present. The state’s case against Northwest was settled in January 2011. Both companies have provided documentation of actions taken to abate all violations and the refinery is subject a follow-up inspection to verify continued correction.