SAN FRANCISCO (AP) — Four California firefighters were in serious trouble almost immediately after a helicopter dropped them near ground zero of what they thought would be a small blaze.

The wind picked up dramatically and unexpectedly, turning the small grass fire into a raging inferno that surrounded the men, forcing them to issue a mayday call over the radio before seeking shelter in emergency tents they carried in their backpacks.

All four were badly burned last month in the Lake County blaze, and a new report by the California Department of Forestry and Fire Protection raises questions about their equipment and training. It notes one firefighter removed his protective gloves and another had problems with his emergency shelter.

The report published this weekend details the trouble the four faced, how they were rescued, and the serious injuries they suffered. The men were among the first victims of the wildfire that turned into one of the most destructive in California history, destroying more than 1,000 homes, killing four people and growing to more than 100 square miles.

The four firefighters hiked up an access road with the expectation of battling a 20-acre fire, according to the review. But the blaze took off unexpectedly, forcing them to flee to a barren goat pen. A nearby hillside then turned into a “wall of fire,” and the intense heat chased the men from the goat pen to a nearby metal barn.

“They could feel their faces burning from the radiant heat,” the report said.

While crouched under the fireproof shelters they got from their backpacks, one of the firefighters tried to sip some water he had with him but found it too hot to drink.

Thick smoke prevented aircraft from dropping water on the men’s position.

The report credits division chief Jim Wright, who lives in Lake County near the site where the fire started, and two other firefighters with responding to the trapped firefighters’ mayday call and racing through the fire in a pickup truck to scoop them up. All four firefighters suffered serious burns and required hospitalization. Two remain hospitalized, one in critical condition.

Wright said he was evacuating neighbors in the area where he lives when he heard radio traffic about the trapped firefighters and realized they were near his home.

A group of firefighters jumped into his pickup truck and they drove through thick smoke until they spotted the glow of the emergency tents.

“I hit my air horn and they popped up,” Wright said.

Fellow firefighters loaded their injured colleagues into the back of his pickup truck and he drove them to a waiting helicopter.

The report raised concerns about the firefighters’ gear and training.

“All firefighters are required to have a safety zone and to communicate the safety zone’s location to everyone,” said Bill Gabbert, a retired firefighter who operates the website Wildfiretoday.com. “They obviously didn’t have a safety zone.”

Gabbert also noted all four suffered burns to their hands, which he said shouldn’t occur if firefighters keep their protective gloves on.

“Personnel MUST wear ALL CAL FIRE APPROVED (personal protective equipment) when engaged in firefighting operations,” the report concluded.

The review said one of the firefighters removed his gloves to peel off the plastic case that melted to his emergency shelter.

Another firefighter couldn’t use his shelter because the plastic case had fused to the tent. So two firefighters shared one small shelter, and two others used their own shelters until helped arrived.

They did their best to shield the heat “away from their already burned faces and hands,” the report stated. “Each of them could see the visible burns to one another’s faces and hands.”

Gabbert said the melted cases could indicate the firefighters waited too long to open their protective shelters.

CalFire said the report was compiled by experts and is intended as a safety and training tool, an aid to preventing future occurrences, and to inform interested parties.

The report suggests fire crews should “practice and prepare for shelter deployment in adverse and extreme conditions.”

CalFire spokesman Dan Berlant called the report a preliminary finding, saying the agency planned a much deeper review of its response to the fire.