GARY, Ind. (AP) — An employee at the Gary Works steel mill has died after an accident at the northwest Indiana facility.

The Lake County coroner’s office says 30-year-old Jonathan Arizzola of Valparaiso died Friday at the U.S. Steel Slab Storage Yard at the largest steel mill in North America. The cause and manner of death remain under investigation.

The Times of Northwest Indiana reports that Arizzola was a maintenance worker, Navy veteran and married father of two.

U.S. Steel spokeswoman Sarah Cassella says an accident occurred at the hot strip mill Friday but that no further details were immediately available. She says the company’s “deepest sympathies are with the employee’s family.”

Protests in recent weeks have accused U.S. Steel of making the mill less safe by laying off and demoting maintenance workers.