A truck-trailer rollover accident on State Route 89 west of the intersection with Highway 395 started a wildland fire around 3:16 p.m. Wednesday.
According to the California Highway Patrol, the driver of the truck sustained serious burns and was taken to Washoe Medical Center by Care Flight helicopter.
State Route 89 on the California side was closed.
U.S. Bureau of Land Management and U.S. Forest Service engines, two federal helicopters and two Nevada Division of Forestry hand crews are working to contain the fire.
About 35 acres were burned on both sides of the highway just below Monitor Pass. Mono County dispatch reported that an estimated 8,800 gallons of "unknown petroleum substance" spilled into Slinkard Creek alongside the road.
Officials from Caltrans, Mono County Environmental Health and California Fish and Game evaluated the hazardous materials.
The truck was reported to be in the creek, but initial reports concluded that most of the fuel in the truck was consumed by the fire.
Three air tankers, two helicopters, two hand crews, five engines and one water tender responded to the blaze. However, the three federal air tankers were later released.
The Monitor fire was 50 percent contained Wednesday evening, and full containment was expected by tonight.
The cause of the accident is unknown.