At least two fires in Robertson County had emergency crews operating at full speed Thursday.

As of 1:30 p.m., all emergency crews had been called in to assist in the fire. The Texas Forest Service provided air support.

The biggest fires were at a chicken operation four to five miles west of Franklin on FM 1644. Witnesses said it was more like an explosion after seeing a single plume of smoke, described as a small mushroom cloud.

Robertson County officials believe they know what started a wildfire that damaged two structures Thursday.

Emergency Management Coordinator Bill Huggins said the fire started when sparks flew from an incinerator at nearby chicken operation. He said the fire quickly spread burning 30 acres, a mobile home and a pick up truck.

Several firefighters were treated for heat exhaustion. One had to be taken to a local hospital, where he was treated and released.