Yes, Grease! The same grease used to lubricate wheel bearings on your motorcycle or the ball joints on a cars chassis. Some grease contains polymers such as Teflon, which when burned can turn into a toxin called nitrofluoric acid. This can happen when you have this type of grease on your hands and you pull out a cigarette and get the grease on the cigarette paper. Smoking the same cigarette can kill you. Always wash the grease off your hands before having a smoke.
I read about the Teflon in grease problem in a book and it reminded me of the movie, Dark Waters, based on a true story about Dupont chemical company when they created Teflon for non-stick frying pans and other tools used in the kitchen. Dupont's research of Teflon created toxic waste, which they dumped into areas near the Dupont research facilities. The toxic waste got into the local water supply and killed people and farm animals. If I remember correctly, Dupont was even found guilty of using their own employees as research guinea pigs.
