Vatican reveals smoke-signal components

The Vatican is revealing what the smoke signals emerging from the Sistine Chapel chimney are made of, after the stir caused by how much more distinct the black smoke in this conclave has been compared to the past.
Black smoke, including sulphur and a coal tar component, rises from the chimney on the roof of the Sistine Chapel in the Vatican City on Wednesday. (Alessandro Bianchi/Reuters)

The Vatican is revealing what the smoke signals emerging from the Sistine Chapel chimney are made of, after the stir caused by how much more distinct the black smoke in this conclave has been compared to the past.

The Vatican spokesman Rev. Federico Lombardi said the black smoke that came Tuesday and Wednesday — indicating a pope had not been elected — was made by adding cartridges containing potassium perchlorate, anthracene (a component of coal tar), and sulphur to the burned ballots.

The white smoke signalling a pope has been elected is produced by potassium chlorate, lactose and chloroform resin.

The Vatican is burning the flares following confusion in past conclaves about smoke colour. Lombardi said that neither the chapel frescoes nor the cardinals inside suffered from the smoke.