SPIRIT LAKE, Iowa (AP) — Authorities say a man was hospitalized after an explosion rocked a plant in northwest Iowa, setting off a fire.

Firetrucks were dispatched to the Polaris Industries plant in Spirit Lake around 9:30 p.m. Monday. Officials say the employees had been evacuated by the time firefighters arrived. The man taken to a hospital hasn't been identified.

Spirit Lake Fire Chief Pat Daly says a blast in the plant's paint room caused the fire. The damage was contained there. It's unclear what caused the explosion.

Polaris employs about 500 people at the plant, producing motorcycles under the Indian Motorcycles brand.