A man whose family’s gender reveal photo shoot sparked a Southern California wildfire that killed a firefighter in 2020 has pleaded guilty to involuntary manslaughter, prosecutors said at the weekend.

The El Dorado Fire erupted on September 5, 2020, when Refugio Jimenez jnr and Angelina Jimenez and their young children staged a photo shoot for their baby gender reveal at El Dorado Ranch Park in Yucaipa, at the foot of the San Bernardino Mountains.

A smoke-generating pyrotechnic device was set off in a field and quickly ignited dry grass on a scorching day. The couple frantically tried to use bottled water to douse the flames and called emergency services, authorities said.

Strong winds stoked the fire as it ran through wilderness on national forest land, about 120km east of Los Angeles.

Charles Morton, the 39-year-old leader of the elite Big Bear Interagency Hotshot Squad, was killed on September 17, 2020, when flames over-ran a remote area where firefighters were cutting fire breaks. Morton had worked as a firefighter for 18 years, mostly with the United States Forest Service.

Veteran firefighter Charles Morton died battling the El Dorado Fire.

On Saturday NZT the San Bernardino County district attorney announced that Refugio Jimenez jnr had pleaded guilty to one count of involuntary manslaughter and two counts of recklessly causing a fire to an inhabited structure. He will be taken into custody on February 23 to serve a year in jail. His sentence also includes two years of probation and 200 hours of community service.

Angelina Jimenez pleaded guilty to three counts of recklessly causing fire to property of another. She was sentenced to a year of summary probation and 400 hours of community service. The couple were also ordered to pay US$1.7 million ($2.7m) in restitution.

“Resolving the case was never going to be a win,” District Attorney Jason Anderson said, offering his condolences to Morton’s family. “To the victims who lost so much, including their homes with valuables and memories, we understand those are intangibles can never be replaced.”

The US Forest Service in September — on the third anniversary of the ignition of the fire — filed a lawsuit against the pyrotechnic device’s manufacturers, distributors and sellers, as well as the couple. The lawsuit alleges that the “Smoke Bombs” used were illegal in California and known to be defective.

Mike Scafiddi, the lawyer for Refugio Jimenez jnr, said the couple have wanted to speak publicly about the fire, its impact on the community and Morton’s death but cannot because of the ongoing federal litigation.

“They have been praying for Mr Morton and his family every night since his death,” Scafiddi said today. “It has touched them profoundly.”

The lawyer said his client had researched and tested the pyrotechnic device before setting it off that day, finding no problems online or during his test.

“It was unforeseeable in all minds,” he said.

The El Dorado Fire burns inside the San Bernardino National Forest in 2020. Photo / Getty Images

Scafiddi said the couple had not, contrary to what’s been said publicly for years, hosted a gender-reveal party. He said it was a photo shoot to discover the baby’s gender with the couple, a few relatives and their children.

“To infer that it was a gathering of multiple people with food and celebration is simply incorrect,” he said. “This was simply taking photographs in what was a beautiful backdrop.”

A lawyer for Angelina Jimenez did not immediately respond to a request for comment.

The blaze injured 13 other people and forced the evacuations of hundreds of residents in small communities in the San Bernardino National Forest area. It destroyed five homes and 15 other buildings.

Flames blackened nearly 92sqm of land in San Bernardino and Riverside counties before the blaze was contained on November 16, 2020.

The fire was one of thousands during a record-breaking wildfire season in California that charred more than 4 per cent of the state while destroying nearly 10,500 buildings and killing 33 people.

Extremely dry conditions and heatwaves tied to climate change have made wildfires harder to fight. Climate change has made the US West much warmer and drier in the past 30 years and will continue to make weather more extreme and wildfires more frequent and destructive.