MT. VERNON —
Unlike the confusion that reigned during the 2005 conclave, the smoke this time around was clear: black during the first two sets of smoke signals, and then clearly white on Wednesday night — thanks to special smoke flares akin to those used in soccer matches or protests that were lit in the chapel ovens to accompany the smoke from the burned ballot papers.
The Vatican on Wednesday divulged the secret recipe used: potassium perchlorate, anthracene, which is a derivative of coal tar, and sulfur for the black smoke; potassium chlorate, lactose and a pine resin for the white smoke.
The chemicals were contained in five units of a cartridge that is placed inside the stove of the Sistine Chapel. When activated, the five blocks ignite one after another for about a minute apiece, creating the steady stream of smoke that accompanies the natural smoke from the burned ballot papers.
Despite the great plumes of smoke that poured out of the chimney, neither the Sistine frescoes nor the cardinals inside the chapel suffered any smoke damage, Lombardi said.