ROCKLAND — The streets of downtown Rockland were filled with smell of burning plastic Sunday morning as a fire was burning in the basement and parts of the first floor of the Redlon & Johnson heating and plumbing wholesale supply store building at 65 Tillson Avenue.

Kyle Willette, an engineer with the U.S. Coast Guard station, also on Tillson Avenue, said he was heading out to check on the Coast Guard vessels, which they do every morning, and spotted smoke coming from the basement windows of the Redlon & Johnson building.

The Maine State Fire Marshal’s Office was called to help determine the cause of the fire, and an investigator from the state’s electrical inspection office will arrive Monday morning to help. The fire remains under investigation, according to the Rockland Fire Department.

Redlon & Johnson is a wholesale distributor of plumbing, heating, cooling, water system, pipe, valves, fittings, and industrial products.

Willette called the fire in to 911, and soon the sound the breaking glass could be heard as the fire and flames burst through the basement windows. The fire’s origin is thought to be at the east end of the building, in the basement.

Rockland firefighters were joined on the scene by Rockport, Thomaston and South Thomaston, as a third alarm was struck soon after the first call went out. Firefighters and equipment from neighboring towns have also been called to stand by the stations of the responding towns in case a call comes in to their towns.

Rockport arrived with two engines and its utility truck, as well as 14 firefighters. Rockland and Rockport firefighters tackled the smoke-filled basement and first floor. The bulk of the damage to the first floor was confined to the office area. The structural damage was confined to the east end of the building.

At 8:30 a.m., smoke could be seen under the eaves and coming through the roof.

Power was cut to the building, making it safer for firefighters to fight the fire, according to reports. Approximately 2,000 gallons of water were used to knock the fire down.

The last of the firefighters cleared the scene at 12:27 p.m.

PenBayPilot.com will update this story with more information and photos.

Editorial Director Lynda Clancy can be reached at lyndaclancy@penbaypilot.com or 706-6657. Editorial Director Holly S. Edwards can be reached at hollyedwards@penbaypilot.com or 706-6655.