Berlin (CNN) -- A chemical accident involving chlorine gas injured nearly 40 people Tuesday at a plant for security technology in Bruhl. Of the 39 victims, seven were seriously injured, according to Markus Brachschoss, a spokesman for the local fire department. Around 300 people were inside the plant at the time of the accident. The incident occurred when two chemicals -- sodium hypochlorite and hydrochloric acid -- came into contact, emitting chlorine gas. Air tests were conducted inside the building where the accident occurred and in surrounding buildings, Brachschoss said. The fire department determined no threat was posed to the surrounding community. More than 46,000 people live in Bruhl, about 10 miles south of Cologne.
Sodium hypochlorite and hydrochloric acid came into contact, emitting chlorine gas . Seven people were seriously injured . The incident occurred at a security technology plant in Bruhl .