A California couple whose gender reveal party set off a wildfire last year has been charged with involuntary manslaughter after a firefighter was killed trying to put the fire out.

San Bernardino County District Attorney Jason Anderson announced Tuesday that the couple pleaded not guilty the day before.

The Hill reports that the fire started on September 5th of last year, when the couple held a gender reveal party at El Dorado Ranch Park, at the foot of the San Bernardino Mountains. But a smoke-generating device set the surrounding dry grass ablaze, and after the couple tried to extinguish the fire with water bottles, strong winds caused the fire to spread through national forests east of the Los Angeles area.

Charles Morton, the firefighter killed on September 17th fighting the fire, was the leader of the Big Bear Interagency Hotshot Squad. The Hill continues that Morton was killed when fires spread to areas where the firefighters were cutting fire breaks, or “gaps in vegetation or other combustible materials meant to slow the spread of fires.”

The Hill adds that the couple “currently faces one felony count of involuntary manslaughter, three felony counts of recklessly causing a fire with great bodily injury, four counts of recklessly causing a fire to inhabited structures and 22 misdemeanor counts of recklessly causing fire to property.” They are scheduled to return to court on September 15th.