Pittsfield-based general contractor Cianbro is in the midst of a major hiring effort for a wide range of skilled construction workers, the company said, adding that it has recruited more than 300 people in recent weeks and plans to hire about 300 more immediately.

The company’s backlog includes the multi-year project to replace the Sarah Mildred Long Bridge in Kittery, installation of tissue machines at a Woodland paper mill, bridge work at the Portsmouth Naval Shipyard, the Gut Bridge replacement in Bristol, and the expansion of the International Marine Terminal in Portland, as well as bridge repairs in Gloucester, Massachusetts, and construction activities at various substations in New Hampshire, Cianbro said.

The company is seeking pipe welders, pipe fitters, millwrights, ironworker/riggers, electricians, construction foremen in all trades, superintendents, carpenters, concrete specialists, mechanical foremen, schedulers and crane operators.

The majority of available work is in Maine, but there are projects up and down the Eastern Seaboard that Cianbro is looking for people to help with, Cianbro said.

Company President Andi Vigue said many of the needed jobs are for long-term projects that would keep those workers employed for an extended period of time. Those working on shorter projects likely would have more work lined up for them by the time those jobs were completed, he said.

“The two largest projects we have in Maine right now are multi-year projects, and they’re just ramping up,” Vigue said.

Construction firms in Maine have struggled to fill open positions for some highly skilled trades because many who were working in those trades prior to the Great Recession have retired, changed professions or moved out of state to pursue jobs elsewhere. In 2006, there were roughly 32,000 state residents employed in construction. Now that number is down to about 23,600.

Representatives of the construction industry organized a news conference last week in South Portland to argue the merits of pending bills that would allow the state to borrow as much as $250 million to improve roads and bridges, build affordable senior housing and upgrade stream crossings and drainage systems statewide. They said approving the bonds would help maintain a steady flow of construction work in the state and help rebuild the workforce.

Vigue said that while he can’t speak for the industry as a whole, his company is experiencing a big uptick in contracts that necessitated the massive hiring effort.

“At Cianbro, it’s changing right now,” he said. “We have larger, longer-duration projects.”

While extensive work experience is preferred, Vigue said it isn’t necessary, as Cianbro offers on-the-job training. Most of the state’s experienced construction workers already have jobs, he said.

Matthew Marks, CEO of the Associated General Contractors trade organization in Maine, said big hiring pushes like Cianbro’s are good for the industry at a time when it is trying to rebuild the workforce and encourage younger residents to seek careers in construction.

Marks said the industry has lost a lot of longtime workers to aging, while others have moved away.

“It’s a little bit different challenge than we’ve had in a long time,” he said.

Maine’s community colleges have not been graduating very many skilled tradespeople, Marks said, which he chalked up to a lack of consistency in the availability of work. But things are getting better, he said.

“It really comes down to that consistency in the workforce,” Marks said. “Hopefully we’re on the right track here.”

Vigue said applicants for Cianbro jobs can visit the company website, cianbro.com, or call its recruiting line at 1-866-242-6276.