A chemical leak at a West Virginia silver recovery business killed two people and sent 19 others to the hospital, including one in critical condition, authorities said. The leak occurred at the Catalyst Refiners plant in Institute as workers were preparing to shut down at least part of the facility, Kanawha County Commission Emergency Management Director C.W. Sigman said.

A chemical gas reaction occurred at the plant involving nitric acid and another substance, Sigman said, speaking at a news briefing. He added that there was "a violent reaction of the chemicals and it instantaneously overreacted." "Starting or ending a chemical reaction are the most dangerous times," Sigman said. Among the injured were seven ambulance workers responding to the leak, officials said.