A man accusing of lying to investigators about the 2014 death of an Alabama oilfield worker in North Dakota pleaded guilty Monday in federal court.

Stephan Reisinger, 50, of Kalispell, Montana, is charged with obstructing an Occupational Safety and Health Administration proceeding stemming from the death of 28-year-old Dustin Payne, of Hazel Green, Alabama. Reisinger was a maintenance manager for Houston-based Nabors Completion and Production Services.

Authorities say Payne was welding inside a tank that had not been properly cleaned and vented, as required by federal law. The welding equipment ignited vapors, causing an explosion.

The plea agreement said Reisinger made false statements in an interview with OSHA, including that he did not know of the hazards and composition of produced water, a liquid waste that is generated by oil wells and which contains flammable chemicals. Reisinger falsely stated that he thought “just water” was in the tanks, the plea deal said.

Reisinger’s federal public defender could not be reached for comment late Monday.

C&J Well Services, the corporate successor to Nabors Completion and Production Services, previously pleaded guilty to charges related to Payne’s death and was sentenced in 2019 to pay $1.6 million to Payne’s estate, as well as a $500,000 fine.