A hot catalytic converter on a vehicle sparked a California wildfire near Yosemite National Park that killed two firefighters, the U.S. Forest Service said.

The blaze that began on the evening of July 13 along Highway 140 in the Sierra National Forest burned more than 96,000 acres before it was fully contained on Aug. 22.

Two firefighters, Braden Varney and Brian Hughes, were killed, and 19 people were injured.

"Investigators believe superheated pieces of a catalytic converter came into contact with dry, roadside vegetation, igniting the fire," the Forest Service said Friday in a news release. Authorities are asking for the public’s help in identifying the vehicle.

Catalytic converters are located on the bottom of vehicles and convert emissions into less toxic forms.

Ten structures were destroyed in the fire, which burned in the Sierra and Stanislaus national forests, officials have said.

The fire prompted the closure of the national park's Yosemite Valley — home to attractions like El Capitan and Half Dome Rock — for nearly three weeks. It was closed to visitors on July 25 and reopened Aug. 14. Other parts of the park were closed longer.

Summer is often the busiest time of year, when travelers flock from around the world. Officials have estimated financial losses of several million dollars. Highway 140 leads to the Yosemite Valley.

The forest service said many wildfires along roadways are caused by motorists, through poor maintenance or other causes.

The massive Carr Fire, also in northern California, that broke out on July 23 and burned more than 229,000 acres in Shasta and Trinity counties, killing at least eight people, was started by a suspected mechanical failure of a vehicle, according to the California Department of Forestry and Fire Protection.

More than 1,000 residences were destroyed in the Carr Fire, the department said. The fire was fully contained in late August.