Abstract  A young man was multitraumatized by a car accident. During the stay in the intensive care unit he had persistent hypoxemia. Various reasons were sought and different treatments were tried, but his severe hypoxemia did not ameliorate. The cause of the hypoxemia remained unclear until his clinical condition improved and we dared to perform a second bronchoscopy which revealed fire extinguisher powder in his airways. The clinical course of the patient is described, as well as the diagnostic and therapeutic measures. Details are given about the methods used for identification of the powder. The problems following unawareness of the condition are discussed.