Seven people are being treated for burns after an explosion at the Taser International plant in Arizona.
One man is critically ill in hospital after the incident in north Scottsdale, while six others are in a stable condition.
It was not immediately clear if all of the injured were Taser employees.
Fire battalion chief Chris Schibi said nine other people who were evacuated from the Taser production facility refused treatment.
It is not yet clear what caused the explosion.
Taser is a developer, manufacturer and distributor of electrical stun guns, body worn cameras and other items that are mainly used by law enforcement and the military.