In August of 1996, Sheriff's deputies investigated the deaths of three individuals suspected to have been overcome by phosphine gas. Phosphine is an extremely toxic gas, and is generally seen in the farming industry where it is used as a grain fumigant. It can also be generated as a by-product during the manufacturing of methamphetamine. Chemicals and equipment consistent with the manufacturing of methamphetamine were noted at the location, as well as an apparent reaction mixture heated to near dryness. Dräger tubes detected an atmospheric phosphine concentration in excess of 0.3 parts per million (ppm), the Threshold Limit Value. Deputies had initially assessed the scene with no protective equipment, raising concerns about phosphine toxicity and the effects of exposure. The objectives of this paper are to describe how phosphine is formed during the manufacture of methamphetamine, to review the toxicity, health effects and symptoms of exposure, to address the safety concerns regarding potential exposure to law enforcement personnel, and to describe the protective equipment available for personnel who respond to clandestine laboratories.