The device ignited four-foot-tall grass at El Dorado Ranch Park on Saturday morning, and efforts to douse the flames with water bottles proved fruitless, Capt. Bennet Milloy of the California Department of Forestry and Fire Protection, known as Cal Fire, said Monday. The family called 911 to report the fire and shared photos with investigators.
No injuries or serious structural damage were immediately reported.
Criminal charges were being considered, but would not be filed before the fire is extinguished, Captain Milloy said. Cal Fire could also ask those responsible to reimburse the cost of fighting the fire, he added.
Gender-reveal celebrations became popular about a decade ago as a way for new parents to learn the sex of their child, often in the presence of family and friends. Simple versions of these celebrations often involve couples cutting open pink or blue cakes, or popping balloons filled with pink or blue confetti.
In April 2017 near Green Valley, Ariz., about 26 miles south of Tucson, an off-duty Border Patrol agent fired a rifle at a target filled with colored powder and Tannerite, a highly explosive substance, expecting to learn the gender of his child.
When placed with colorful packets of powder and shot at, Tannerite can fill the air with colorful residue for gender-reveal parties: blue for boys or pink for girls.
The resulting explosion sparked a fire that spread to the Coronado National Forest. It consumed more than 45,000 acres, resulted in $8 million in damages and required nearly 800 firefighters to battle it. The border agent immediately reported the fire and admitted that he started it, the United States Attorney in the District of Arizona said in September 2018.