Several area fire crews battled a tractor fire Monday morning on Route 137 in Knox.

Around 10:45 a.m., a large tractor with a plow blade attachment owned and operated by Michaud Farms of China was traveling east on Route 137 in Knox when it caught fire in the area of 1039 Belfast Road.

Knox Fire Chief Hank Elkins said it is unclear what caused the vehicle to ignite.

The operator said he smelled something as he crested the hill, right before the tractor caught fire, Elkins said. The operator was not harmed.

Flames and thick billowy smoke could be seen from a distance, while firefighters doused the tractor.

Elkins said the fuel tank exploded, sending ignited fuel within 10 feet of a chicken house.

"When the back tires blew, they were filled with calcium, to weigh the tractor down, and it actually put the fire going towards the chicken house out," Elkins said.

The fire chief said the tractor is a total loss and the Department of Environmental Protection is testing where fuel spilled. DOT will return to remove the topsoil where the fuel came in contact with it, he said.

Elkins coordinated efforts from Brooks, Freedom, Morrill and Waldo fire departments.

No additional injury or damage was reported.