Black Smoke, White Smoke

For black smoke, the Vatican Information Service said, the compound blends potassium perchlorate, anthracene and sulfur. White smoke heralding a new pope comes from a mixture of potassium chlorate, lactose and rosin, “a natural amber resin obtained from conifers.”

Before 2005, the black smoke was “obtained by using smoke black or pitch and the white smoke by using wet straw,” the Vatican said.