At the last conclave, in 2013, the Vatican said it used a mixture of potassium perchlorate, anthracene and sulphur to produce black smoke, and potassium chlorate, lactose and rosin for white.

Vatican firefighters were seen on the roof of the Sistine Chapel installing the chimney, a key moment in the preparation for the May 7 conclave.

VATICAN CITY (AP) — Black smoke poured out of the Sistine Chapel chimney on Wednesday, signalling that no pope had been elected as 133 cardinals opened the secretive, centuries-old ritual to ...

VATICAN CITY (AP) — Black smoke poured out of the Sistine Chapel chimney on Wednesday, signaling that no pope had been elected as 133 cardinals opened the secretive, centuries-old ritual to ...

Watch a live feed of the Sistine Chapel's chimney as the conclave of Catholic cardinals meets in Vatican City to choose the next pope. When the new pope is chosen, white smoke will pour out from ...

Vatican firefighters were seen on the roof of the Sistine Chapel installing the chimney, a key moment in the preparation for the May 7 conclave. Watch NBC Bay Area News free wherever you are ...

Vatican firefighters were seen on the roof of the Sistine Chapel installing the chimney, a key moment in the preparation for the May 7 conclave. Stream NBC4 newscasts for free right here, right now.