From AJC.com:

An Atlanta firefighter suffered second-degree burns when the heat from a house fire and his body sweat combined to form steam inside his protective suit, according to fire department spokesman Capt. Jolyon Bundrige.

Bundrige said the firefighter was exercising when the call came to respond to a house fire on Ridge Avenue in northwest Atlanta, so he just put on his gear. Bundrige said he was “sweaty and clammy” from his workout and that created a “steam burst” once the fire heated up the suit.

The firefighter, whose name was not released, was taken to Grady Memorial Hospital, treated and then discharged Monday night.