What happened when the FBI began using tear gas at Mount Carmel on April 19, 1993?

On April 19, 1993, at approximately 6:00 am, the FBI began spraying tear gas into the Mount Carmel compound to force the Branch Davidians to surrender. Shortly after the operation commenced, the group began firing weapons.1

For more than five hours, armored vehicles punched holes into the building's walls and deposited 400 tear-gas canisters inside. The assault concluded at 11:40 am. Approximately 25 minutes later, the Branch Davidians set several fires, and gunfire was heard within the complex at 12:25 pm. Due to safety concerns, firefighters were delayed in entering the area, and by the time they arrived, the compound was destroyed. Nearly 80 people died in the fire, including leader David Koresh.12

While the government long maintained it did not start the fire, it later admitted in 1999 that some of the tear gas used was flammable. However, a subsequent investigation led by John Danforth concluded in 2000 that the U.S. government did not cause the fire nor shoot at the compound.12