Breathing Teflon tape fumes
The reliability of humans as indicators of Teflon toxicity was confirmed in a mass poisoning incident involving inhalation of Teflon fumes from heated Teflon tape.
One year after DuPonts cigarette experiments, the Air Force conducted human studies following a C54 flight in which all the passengers and crew became mysteriously ill [Nuttall et al. 1964]. The incident is recounted in a review of fluoropolymer safety conducted 13 years later by the National Institute for Occupational Safety and Health (NIOSH): Within 1 hour of takeoff, most of the passengers and two of the crew members had chest discomfort and general malaise, including chills, nausea, and respiratory distress in some. One passenger vomited and collapsed and was found 5-10 minutes later in a cyanotic state with a weak and rapid pulse. A second passenger had severe respiratory distress and moderate collapse. Six passengers were incapacitated, and five were given oxygen... On arrival, three passengers required hospitalization, and everyone aboard the plane except one co-pilot had experienced effects, which persisted after the plane landed. Four people who collected air samples from the plane after it landed also developed a fever reaction [NIOSH 1977].
A series of human experiments was designed to pinpoint the cause. Up to 28 volunteers in six separate trials were exposed to fumes from the exhaust system of the airplane. After ruling out multiple gases and other potential causes, the toxicity was linked to Teflon tape that had covered part of the exhaust manifold, and that had heated up during flight to offgasing temperatures.