All of the victims were believed to be part of a crew from utility company CenterPoint Energy that was trying to shut down a gas line, FOX 51 of Tyler, Texas, reported.
The extent of the injuries was not immediately known.
At least one house was damaged in the blast and fire, with an unknown number of nearby residents evacuated as the emergency response got underway, the station reported.
Responders set up a 500-foot perimeter around the blast and fire scene, FOX 26 of Houston reported.
Firefighters were able to get the blaze under control, the report said.