HUDSON, S.D. -

Federal investigators have found multiple safety violations at a South Dakota ethanol refinery expansion project after a worker died in May.
    
The Occupational Safety and Health Administration cited a contractor, North Dakota-based Bilfinger-Westcon, with five major safety violations.
    
Investigators found 38-year-old Zenon Navarrete was removing a vent line May 6 when ethanol spilled onto him, flowed through a grated floor and was ignited by welding operations on a lower floor. The fire engulfed the pipefitter.
    
Inspectors found Bilfinger-Westcon allowed welding without ensuring flammable liquids weren't present. OSHA also cited the refinery owner, Sioux River Ethanol LLC, which operates as POET Biorefining.
    
Bilfinger-Westcon had no immediate comment. A spokesman for POET Biorefining said safety is the first priority and the company is reviewing OSHA's report and evaluating its future relationship with the contractor.