Fire crews from the U.S. Forest Service, Payson, Christopher-Kohl's and Diamond Star responded about 8 a.m. Wednesday morning to an overturned diesel fuel tanker on Highway 260 near Camp Tontozona.
Tonto National Forest duty officer Vinnie Picard said the ground fire caused by the overturned tanker had been contained at about one-half acre but the situation remained volatile.
"We have to get the right equipment out there to battle the diesel fire," he said.
In addition to four engines and the ground crews, the fire was being fought by helicopters and air tankers.
The blaze has been named the "Kohl's Fire" because of its location near Kohl's Ranch.
Reports indicate residents of some nearby homes were in the process of a voluntary evacuation.
Black smoke from the burning diesel fuel was visible in Pine.