Update, Nov. 11 at 10:30 p.m.
Someone associated with the business confirmed that the source of the fire was an L20 Volvo loader stored in the building, perhaps from a short circuit in the wiring.
Update, Nov. 11 at 8:50 p.m.
Investigations continue into the evening, as the state police have also arrived on the scene of the fire. Patch has learned that surveillance cameras within the business have given investigators clues as to the cause of the fire.
Route 10/202 remained closed in both directions near the site.
Update, Nov. 11 at 6:30 p.m.
Firefighters were concerned about the fire spreading because of propane tanks, diesel fuel and gasoline stored on site.
The entire center of the building was in cinders by 6 pm.
The Office of the State Fire Marshal is investigating the scene.
A major fire broke out at H.P. Builders on Salmon Brook Street a little before 4 p.m. on Friday afternoon.
Beginning in a vehicle bay, black smoke billowed from the middle of the three-section building. The fire quickly consumed the vehicle, and explosions were heard shortly after the blaze broke out.
Lost Acres Fire Department arrived on the scene and quickly set up hoses to try to contain the fire. Fire engines from Simsbury, East Granby and Southwick were on the scene in minutes.
Salmon Brook Street is closed in both directions for emergency vehicles deal with the emergency.
There were no reports of injuries. Dozens of firefighters assisted in fighting the blaze, and employees of the construction company removed tanks and other flammable materials from the remainder of the building.
The fire appeared to be contained as of 4:45 p.m. as rain began to fall.
Check back to The Granbys Patch for more details.