CABAZON, Calif. >> Two firefighting helicopters collided while responding to a blaze in Southern California, sending one to the ground in a crash that killed all three people on board.

The accident late Sunday afternoon in the desert about 85 miles east of Los Angeles involved a huge Sikorsky S-64E and a smaller Bell 407.

“Unfortunately, the second helicopter crashed and tragically all three members perished, which included one Cal Fire Division chief, one Cal Fire captain and one contract client pilot,” Cal Fire Southern Region Chief David Fulcher told a news conference early today.

Fulcher did not identify the victims.

Cal Fire and Riverside County Fire Department resources had been dispatched to a structure fire near the intersection of Broadway Street and South Ronda Avenue in the community of Cabazon shortly after 6 p.m. That blaze spread into surrounding vegetation and a full wildland fire dispatch was initiated, which included multiple airplanes and helicopters.

“That’s not an uncommon dispatch for a wildland fire, to send those resources,” Fulcher said.

Cal Fire said in a social media post at the time that the fire was burning “in light flashy fuels with a moderate rate of spread” and had spread over approximately 3 acres (1.2 hectares).

While battling the blaze, the two helicopters collided. The crash caused an additional 4-acre fire, which was extinguished. The Sikorsky landed safely.

The Bell helicopter was being used for observation and coordination, Fulcher said. The Sikorsky can drop water or retardant on fires. Fulcher said he did not know whether it was loaded at the time of the crash.

“Although this was a tragic event, we are also thankful today that it wasn’t worse,” Fulcher said. “The individuals in the first helicopter were able to able to land safely without incident and no one else was hurt.”

The pilot of the crashed helicopter was flying under contract with the California Department of Forestry and Fire Protection. The Sikorsky and its two-person crew were also under contract.

Cal Fire operates its own fleet of dozens of aircraft but also contracts with commercial companies for additional helicopters and airplanes that are on standby at bases statewide.

The crash is being investigated by the National Transportation Safety Board.