(USA Today) -- The thin, heat-resistant emergency shelters that firefighters carry into battle offer some protection but cannot deal with everything an out-of-control wildfire can throw at them.
Prescott Fire Chief Dan Fraijo said the 19 firefighters who died overnight in a wildfire in Arizona had to deploy the emergency shelters when "something drastic" occurred.
"One of the last fail safe methods that a firefighter can do under those conditions is literally to dig as much as they can down and cover themselves with a protective - kinda looks like a foil-type, fire-resistant material - with the desire, the hope at least, is that the fire will burn over the top of them and they can survive it," he said.
From accounts of firefighters who have survived such an ordeal, it is a horrendous experience.
In last month's wildfire along the California-Nevada border near Reno, two firefighters had only seconds to wrap themselves up in the material and hunker down.
"They were in their tents for 25 minutes wondering if they'd live or die, and most people can't imagine what that would feel like," fire commander Rich Hawkins told The Associated Press.
In a 2001 fire in Washington state, firefighter Jason Emhoff said it was like "being run over by a freight train," his father, Steve Emhoff, told the AP.
Jason Emhoff suffered burns over 40% of his body as temperatures climbed about 500 degrees. He lost some use of his hands because he was forced to grip the sides of the shelter without leather gloves.
Although Jason Emhoff eventually returned to the Forest Service to fight fires but does not like to discuss his experience, his father told the AP.
"It's changed his life," Steve Emhoff said of his son.
The tent-like shelters are not able to withstand direct flames but rather provide some protection and oxygen against the hot winds and poisonous gas.
"When we die in a fire, we die long before the flames consume us," Hawkins said. "It's the superheated air that destroys your lung tissue. It's a terrible way to go and it's our greatest fear as firefighters."
In the 2001 blaze, firefighter Rebecca Welsh of the same squad as Emhoff squeezed two civilian campers into her shelter. She suffered second-degree burns because she couldn't fit entirely into the crowded tent.
"It's a last-ditch measure for survival," Hawkins said.
Contributing: The Associated Press