The chimney atop the Sistine Chapel has been installed ahead of the upcoming conclave that will elect the 267th Pope following the death of Pope Francis. The Vatican Press Office over the weekend released images and videos showing the Vatican fire brigade atop the chapel’s roof, installing the chimney that will signal the outcome of the secret voting process.
The conclave is set to begin on Wednesday, May 7, 2025. During the voting, black smoke will emerge from the chimney if at least 89 of the 133 Cardinal electors fail to reach a consensus on the next Pope. White smoke will signal that a new Pope has been elected to lead the Catholic Church into the future.
In each round of voting, the Cardinal electors will fold their ballots twice and place them into a chalice. Selected cardinals will then count and record the votes. If no decision is reached, the ballots are burned in a stove, producing smoke with the help of a second stove to ensure a clear signal.
The black smoke is produced using a mixture of potassium perchlorate, anthracene (a coal tar component), and sulfur, while the white smoke is made from potassium chlorate, lactose, and chloroform resin. These chemical recipes were revealed during the 2013 conclave by The New York Times. The Vatican adopted the use of chemical cartridges after past mishaps, including in 1958 when damp straw used to create black smoke failed to ignite properly, causing confusion as the smoke initially appeared white.
The tradition of signaling with black and white smoke dates back to the early 1900s, according to NBC News, which also noted previous experiments with smoke bombs that produced clearer colors but filled the chapel with smoke. Meanwhile, preparations for the conclave have included spiritual observances. On Sunday afternoon, Cardinal Protodeacon Dominique Mamberti presided over the ninth and final Mass in suffrage for Pope Francis at Saint Peter’s Basilica, with the participation of the College of Cardinals.
Pope Francis, who died at age 88, was buried on April 26 at the Basilica of Saint Mary Major in central Rome. Since his burial, the Cardinals have held several congregations to pray and reflect on the future of the Church. According to the Vatican program, the Cardinal electors will convene for General Congregations on Monday and Tuesday ahead of the conclave.
On Wednesday morning at 10:00 AM, they will gather at St. Peter’s Basilica for a pre-conclave Mass to invoke the Holy Spirit’s guidance. Later that afternoon at 4:30 PM, the 133 Cardinal electors will assemble in the Pauline Chapel to pray the Litany of the Saints before processing into the Sistine Chapel.
The Master of Pontifical Liturgical Ceremonies will then proclaim “extra omnes,” ordering everyone not involved in the conclave to leave the chapel. Afterwards, both the non-elector Cardinals (those over 90) and the Master of Ceremonies will exit, and the first round of voting will begin. The Cardinal electors will cast their votes four times daily — twice each in the morning and afternoon — until a new Pope is elected.