Updated

Authorities say seven people are being treated for burns after some sort of explosion at the Taser International plant in north Scottsdale.

Scottsdale Fire Department officials say one man was transported from the scene in critical condition Thursday while six others were hospitalized in stable condition.

It wasn't immediately clear if all of the injured were Taser employees.

Fire Battalion Chief Chris Schibi says nine other people who were evacuated from the Taser production facility refused treatment.

Schibi says it's still unclear how the explosion occurred and what it involved.

He says the call came in to the department about 4:15 p.m.

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.