EAST CHICAGO, Ind. (AP) — A steelworker has died at ArcelorMittal’s Indiana Harbor steel mill in East Chicago while operating a golf cart-style buggy.

Company spokeswoman Mary Beth Holdford says the worker died early Monday while working at the steelmaking complex’s No. 3 Continuous Annealing Line.

Additional information was not immediately released and it wasn’t clear if the worker died in an accident while operating the buggy or as the result of a medical condition.

Holdford tells The (Northwest Indiana) Times the incident is under investigation by both the Luxembourg-based steelmaker and the United Steelworkers union.

The steelworker was not immediately identified but Holdford says the company “extends our deepest sympathy to family and friends of the deceased” and is offering employees onsite counseling services.