LINCOLN, Neb. (AP) — Authorities say a buildup of carbon monoxide gas has killed one person and caused three others to be hospitalized in Lincoln.

Police and medics were called to a north Lincoln home around 3 a.m. Wednesday. Officer Angela Sands says four people found there were taken to a hospital, where one of them died. No names have been released.

Fire Battalion Chief Jim Bopp says a medic’s carbon monoxide detector went off at the home. Bopp also says Black Hills Energy workers blamed the deadly gas buildup on a water heater problem.