BANGOR, Maine — After 75 years, Webber Energy Fuels is getting out of the gas station business.

The Bangor-based company just sold six of its retail gas stations and convenience stores to Irving Oil of New Brunswick, including locations in downtown Orono and on Hogan Road in Bangor.

Officials are actively looking into selling the remaining stores, which number about half a dozen, Mike Shea, president and CEO of Webber Energy, said Wednesday afternoon.

“Things always change. Sometimes they change a little more dramatically than other times,” Shea said. “As times have changed, it’s just a part of the business that right now it doesn’t make sense for us to be in.”

Webber Energy is going to focus on its core heating oil and propane business and wholesale gasoline distribution operation, Shea said, adding he was pleased that Irving has rehired all the approximately 70 store employees.

Shea said that razor-thin profit margins and rising operating costs led to the decision to sell to Irving Oil, which has its own marine terminals and oil refineries in addition to hundreds of gas stations and stores.

“It’s always survival of the fittest. They have strengths in that area that we don’t have,” he said.

Lars Trodson, the U.S. spokesman for Irving Oil, said from his office in Portsmouth, N.H., that the company is “very much positioned for growth.”

“We’re growing our businesses in the best way,” Trodson said Wednesday. “Maine has been a great business location for us since the early 1970s. We’re definitely growing in Maine in 2009 and beyond.”

Irving Oil owns 290 retail operations in Maine, New Hampshire, Massachusetts and Vermont, and nearly 300 in Canada.

While the company intends to continue its expansion in Maine, Trodson said, quantity won’t come at the expense of quality.

“We’re not looking to have a monopoly or to dominate the industry in Maine,” he said in a statement. “We don’t think in those terms. … What we do is concentrate on serving our customers well and on providing quality products, and if we continue to do that, we’ll also continue to grow.”

Shea said the state had to approve the gas station purchases because it does “keep an eye” on store concentration.

Although Irving now owns the two former Webber stores in Orono and Bangor — as well as two in Freeport, one in North Windham and one in Falmouth — the signs won’t all be the same.

The Orono, Bangor and Freeport sites will be managed by a company called Couche-Tard and will have Circle K stores.

The sites in North Windham and Falmouth will be managed by Nouria Energy with Lil’ Mart stores.

However, the gas pumps and pump canopies all will be branded Irving, Trodson said.

Shea said he has mixed emotions about the change of ownership.

Webber Energy Fuels was founded in 1935 with four employees and two delivery trucks and now employs more than 600 people in Maine.

“The board of directors just realized that if we stick to what we do best and manage those challenges, that’s where we want to put our energy and our effort,” Shea said.