BOOTHBAY -- Fire swept through a large boatyard Friday, destroying a century-old building and two tugboats under construction. The blaze caused an estimated $30 million in damages and left more than 80 employees without work.

It took dozens of firefighters from several towns nearly four hours to bring the fire at Washburn & Doughty Associates under control and crews are expected to remain on the scene today to prevent flare-ups of the smoldering wreckage. Firefighting was hampered by frequent explosions of diesel fuel, acetylene and propane gas tanks.

The huge, 50,000-square-foot assembly building, which housed the tugs and company offices, was completely destroyed by the fire. Black smoke rising from the fire could be seen from miles away.

By the time firefighters were focusing on reaching hot spots, all that was left was a large aluminum door that stood at one end of where the building had been, and a metal stairway at the other end. Both looked ready to topple almost anytime. In between were the under-construction metal tugs, covered in soot and steaming whenever they were hit by the spray from fire hoses.

The fire was so intense that the paint melted on the side of a worker's pickup in the employee parking lot about 100 feet from the building, located in the village of East Boothbay.

All the Washburn & Doughty shipyard employees escaped unharmed from the fire, which broke out about 9 a.m. Before fire companies arrived, several workers tried to put out the flames, using fire extinguishers and a hose connected to a landing craft that was berthed at the pier and was equipped to draw water from the harbor.

Boothbay Fire Chief Dick Spofford said two firefighters were overcome by heat, but they were treated at the scene. He said about a dozen towns sent equipment and firefighters to help with the blaze. Red Cross volunteers circulated, handing out sandwiches and bottles of cold water.

"We've got almost all of Lincoln County here," Spofford said

Several Coast Guard boats also arrived. One kept other boats away from the area that was burning and another took firefighters with a portable pump to areas that land-based crews couldn't reach.

Aaron Koss, a 17-year-old whose house is adjacent to the boatyard, said he was awakened Friday by a car alarm from the Washburn & Doughty parking lot next to his house. Then he heard a fire alarm from the yard and smelled the smoke that the wind was carrying toward his house. It wasn't long, he said, before he saw flames coming out of the building.

"Of course, it was going to go up fast with dry wood and (being) over 100 years old," Koss said. He noted that his stepfather's great-grandfather built the building in the late 1800s for what was then called Rice Brothers boatyard.

The fire started near the roof and water-side doors of the cavernous wood frame building, which had asphalt shingle siding, said Dan Young, senior investigator for the Fire Marshal's office. One of the tugboats under construction was within a few feet of the side of the building, Young said, and investigators are trying to determine what work was going on in that part of the boat prior to the fire. He said workers might have been cutting, welding or grinding and sparks from "any one of those could do it."

Young said he and other investigators will rely on interviews with workers to help determine the cause. His supervisor said there won't be much physical evidence to go by.

"The building's not there anymore, so the building's not going to tell us much," Sgt. Ken Grimes of the Fire Marshal's office said.

Gov. John E. Baldacci put out a statement Friday afternoon pegging damage at $30 million or more.

Young noted that the engines for the tugs alone are worth several million dollars each.

The Red Cross opened up an evacuation center at Boothbay Region Elementary School, but closed it later Friday afternoon after power was restored to the neighborhood around the boatyard. None of the homes was damaged by the fire and the wind Friday pushed most of the smoke over the water and away from the neighborhood.

Bruce Washburn said he and partner Bruce Doughty started the boat-building business in 1977. Initially, he said, they built fishing boats, ferries and research vessels before turning to tugboats in recent years.

The company provided year-round manufacturing jobs, which aren't plentiful in the tourism-dependent Boothbay Harbor region. In addition to the 85 employed directly by the shipyard, Washburn said, the company also employed dozens of subcontractors.

Washburn said business had been very good in recent years. The tugboats under construction were 92-, 98-, and 121-feet-long, part of a six-boat contract with a tug company from Connecticut.

The company considered moving to Wiscasset last year to expand, but ultimately decided to stay in Boothbay. It recently bought a small piece of waterfront land next to its existing site.

Washburn hopes to rebuild and said the yard was insured.

"Now we'll see how good it is," he said of the insurance coverage.

Baldacci and members of the state's congressional delegation pledged to provide whatever state and federal support is needed to help the company and the community recover.

Baldacci said representatives from the Department of Labor's Rapid Response team would visit the site Monday to offer assistance to workers. Tim Hodgdon, a nearby business owner, has offered building space and assistance to Washburn and Doughty. Baldacci also said he plans to tour the facility Tuesday.