BROWNVILLE, Neb. — Fire crews attached to the Cooper Nuclear Station in southeast Nebraska extinguished a blaze Saturday morning that was discovered near a pipe.

The Nebraska Public Power District — which owns and operates the facility near Brownville, Nebraska — said an “unusual event” was declared at 9:04 a.m. Saturday. That designation was implemented when personnel on scene found hazardous gas in the plant’s basement.

Cooper officials said fire was noticed within a pipe chase — the space surrounding the unit — while the gas was being investigated.