LOS ANGELES, United States (AP) — A firefighter died battling a wildfire in California that officials said was sparked by a device used to reveal a baby’s gender.

The death happened Thursday in the San Bernardino National Forest as crews battled the El Dorado Fire, the US Forest Service said in a statement.

The fire erupted earlier this month from a smoke-generating pyrotechnic device used by a couple to reveal their baby’s gender, the California Department of Forestry and Fire Protection, or Cal Fire, said.

The name of the firefighter was being withheld until family members are notified. The cause of the death was under investigation.

“Our deepest sympathies are with the family, friends and fellow firefighters during this time,” Forest Service spokesperson Zach Behrens said in the statement.

No other information was released about the firefighter, the agency the firefighter worked for or the circumstances of the firefighter’s death. Behrens said in a telephone interview he could not comment beyond details in the statement

A Cal Fire statement said it was the 26th death involving wildfires besieging the state.

Cal Fire said earlier this month that the fire was ignited September 5 when a couple, their young children and someone there to record video staged the baby gender reveal at El Dorado Ranch Park at the foot of the San Bernardino Mountains.

The device was set off in a field and quickly ignited dry grass. The couple frantically tried to use bottled water to extinguish the flames and called 911.

Authorities have not released the identities of the couple, who could face criminal charges and be held liable for the cost of fighting the fire.

Shortly after the fire began, San Bernardino County District Attorney Jason Anderson issued a statement saying he was aware of the community’s concerns about how the fire started.

“If investigative reports are filed with our office, we will review all facts, evidence, statements, and reports to determine what criminal charges, if any, need to be filed,” Anderson said.

In 2017, a massive Arizona wildfire was accidentally started by an off-duty Border Patrol agent who shot a target filled with an explosive blue powder at a gender reveal. The fire burned 73 square miles (189 square kilometres) and caused US$8 million in damage. The agent was charged with a misdemeanour and sentenced to probation.

The El Dorado Fire has burned more than 33 square miles (85.4 square kilometres) and was about 66 per cent contained, according to Cal Fire. The fire has destroyed 10 buildings and damaged six others.

Milder weather was helping more than 18,500 firefighters battling more than two dozen major wildfires in California, Cal Fire said.

More than 7,900 wildfires have burned more than 5,300 square miles (13,727 square kilometres) this year, including many since a mid-August barrage of dry lightning ignited parched vegetation.