TEKAMAH, Neb. (AP) — Authorities have identified the man who died after driving near anhydrous ammonia that was leaking from an underground pipeline in northeast Nebraska.

The Burt County Sheriff’s office says 59-year-old Phillip Hennig of Tekamah, Nebraska, died after coming in contact with the chemical.

The leak in the pipeline operated by Magellan Midstream Partners, of Tulsa, Oklahoma, was reported Monday evening about eight miles north of Tekamah, which is nearly 40 miles from Omaha.

Authorities are still trying to determine why the pipeline leaked.

Anhydrous ammonia is a farm fertilizer with suffocating fumes that cause breathing difficulty and irritation to eyes, nose or throat.