The El Dorado Fire erupted on Sept. 5 last year when a couple lit a smoke bomb at a baby gender reveal party—the blaze went on to scorch 36 square miles of Southern California, injure 13 people, and kill a firefighter. Now, the couple who ignited the smoke bomb have been charged with involuntary manslaughter. According to NPR, the couple—Refugio Manuel Jimenez Jr. and Angela Renee Jimenez—pleaded not guilty to the manslaughter charge, as well as a string of other related felony and misdemeanor counts. The fateful gender-reveal event was held at El Dorado Ranch Park in Yucaipa, at the bottom of the San Bernardino Mountains. On Sept. 17, 39-year-old firefighter Charles Morton lost his life in the flames. “Obviously, he wouldn’t have been out there if this hadn’t started in the first place,” said San Bernardino County’s district attorney, Jason Anderson, at a press conference on Tuesday. “He’s fighting a fire that was started because of a smoke bomb. That’s the only reason he’s there.”