The cause of a fire that occurred Friday at Graber Industries in Constantine Township is still undetermined.

The Centerville and Three Rivers Fire Departments were dispatched to the scene shortly before 10 a.m. Friday after reports of a barn fire.

Members of the arriving units found one of the barns completely submerged and thick smoke billowing from a second barn. The proximity of the barns and a high heat load caused the blaze to spread rapidly. Four barns were destroyed by fire. Two other barns on the site were not damaged.

Firefighters remained on site until 8:15 p.m. Friday.

The company, formerly G&G Salvage, houses a variety of building materials, including RV and home supplies, such as carpeting, as well as plumbing and electrical supplies.

Centerville Fire Department chief David Miracle said a few firefighters suffered from heat exhaustion, but nothing serious. Beyond that, no other injuries were reported. Everyone had come out of the barns at the time of the fire.

“We would also like to thank the community for all their support with food and water,” Miracle said. “It was much appreciated.”

He also thanked responding departments from Three Rivers, Fabius Park, Constantine, White Pigeon, Tri-Township, Sturgis, Burr Oak, Colon Community, Leonidas, Mendon and Porter Township.

The St. Joseph County Sheriff’s Department, St. Joseph County Victim Services, Michigan State Police and Robert’s Excavating also assisted.