EL DORADO, Kan. (AP) — An oil refinery in El Dorado where an employee died in 2017 will pay a $1.6 million fine for violating the federal clean air law.

The Environmental Protection Agency announced Tuesday that HollyFrontier’s failure to follow the law contributed to a fire that killed the employee. The EPA says the company did not comply with requirements intended to prevent the accidental release of hazardous substances.

The federal agency says a heater tube ruptured at refinery, causing the fire. The agency says a subsequent investigation found HollyFrontier did not design or maintain a safe facility or inspect and replace heater tubes.