BANGOR – A development firm from Chestnut Hill, Mass., has struck a deal with the owners of a 50-acre parcel off Stillwater Avenue.

John Corbett of W/S Development Associates confirmed Friday his company’s plans to acquire the parcel from the heirs of the Irene L. Averill estate. The parcel, recently rezoned commercial at the heirs’ request, is being eyed as the site for a multimillion-dollar retail shopping center.

“It’s still in the concept stages, so it’s premature [to disclose] who any of the tenants might be,” Corbett said in a telephone interview Friday. “We are marketing the site and we have had a lot of interest.”

Though Corbett said he could divulge few details now because the project is still in the planning stages, he did say the shopping center would be valued at “tens of millions” of dollars and could add as many as 1,000 jobs to the local economy. He said the company plans to submit a site plan for the city’s approval next spring.

W/S Development now is actively marketing the site to potential retailers, Corbett said. He said he was unable to disclose what anchor or other retailers might be moving in.

The company recently completed and opened a 125,000-square-foot Target store on a 12-acre parcel next to The Home Depot in the Bangor Mall area.

A look at the company’s Web site, however, listed a variety of major tenants for its other projects in and outside Maine, among them Hannaford, Loews, Staples, Bloomindales, Wal-Mart, PetsMart, Kohl’s, Old Navy, Gap and Barnes and Noble.

The Averill site is located near but not adjacent to the Penjajawoc marsh and stream, which are located in a resource protection zone.

Because of the site’s proximity to Penjajawoc, Corbett said, the company has been working proactively to address any concerns that area environmental groups might have, in part to avoid a protracted battle like that which led to the downfall of a Wal-Mart Supercenter proposed for the opposite side of the stream.

During rezoning deliberations this summer, Cindy DeBeck of Newburgh, the Averill Estate’s executor, agreed to abide by a 600-foot setback from the Penjajawoc, a concession hailed by environmentalists, chief among them Bangor Area Citizens for Responsible Developmen.

The minimum required setback originally consisted of the land within 75 feet of the boundary of the resource protection area in which the Penjajawoc Marsh and stream are located. The estate’s decision to expand the buffer by 525 feet, bringing the total to 600 feet, was prompted by suggestions from city councilors hoping to broker a deal between conservation groups and DeBeck.

City Manager Edward Barrett said Friday that W/S Development and Civil Engineering Services, a Brewer engineering firm retained by the Averill Estate, have been collecting a great deal of data about the site and the Penjajawoc.

That information, he said, will be helpful as a soon-to-be-appointed ad hoc citizens group begins work toward developing a watershed management approach that strikes a balance among protecting the environment, making sure landowners can earn income from their properties and allowing Bangor’s commercial tax base to grow.

Barrett also said the tax revenue from the project would help offset some of the effects the city’s homeowners have been feeling because residential property values here have risen more quickly than commercial and business properties.