The company that owns the Mount Tom power plant is keeping mum about the implications of its recent decision to go off line for a year. But environmental groups are celebrating the move as a step toward the long-overdue closing of the coal-burning plant, and one more reason to start planning for life after its closure.

Earlier this month, GDF Suez, which owns Mount Tom Station, had its application for a “dynamic de-list bid” for 2016—a jargony way to saying it won’t produce electricity that year—approved by ISO New England. That means ISO New England, which oversees the regional electricity market, won’t count Mount Tom among the plants from which it purchases electric power to meet demand in the region. While GDF Suez has declined to comment to the media about the decision, an ISO New England spokeswoman told the Springfield Republican that the plant could still sell power through the wholesale market.

But Coal Free Massachusetts and Action for a Healthy Holyoke, a coalition of community groups that would like to see the plant shut down by next year, note that other Massachusetts coal-fired plants have followed the same process as they prepared to shut down permanently.

They also say that ISO New England’s approval of the plant’s de-list bid “is a strong indication that Mt. Tom could permanently retire without any impacts on electric reliability for customers.”

Mount Tom Station, which was built in 1960, has long been a target of groups concerned about the effects of its emissions on public health, particularly given that the Holyoke area has a higher rate of asthma and asthma-related emergency room visits than the state average, according to a 2009 report from the Mass. Department of Public Health.

Critics also point to the plant’s effects on the Connecticut River; in recent years, the plant owners have faced government fines for releasing pollutants into the river. In 2011—two years after installing a reported $55 million in equipment to reduce air pollution—plant owners reached an agreement with the Mass. Attorney General to address ongoing air pollution problems.

In recent years, as demand for coal-fueled power has dropped, dozens of Mount Tom Station workers have been laid off. AHH is calling on GDF Suez to work out a transition plan with the 18 people the group says still work there. “We don’t want them to pay the price for the company’s dirty industry,” member Virgenmina Perez said in a statement released by the group.

Last fall, the state set up a task force—led by Energy and Environmental Affairs Secretary Rick Sullivan, the former Westfield mayor and potential 2014 gubernatorial candidate—to help communities that host coal-powered plants prepare for those plants’ eventual closures, addressing, for instance, the loss of jobs and municipal taxes and cleanup and reuse of the facilities.

In addition, the city of Holyoke has established a citizens’ advisory group to look into possible uses of the plant after its expected closure. On April 3 at 7 p.m., AHH will host a public meeting on the plant’s future at Heritage State Park’s Visitors’ Center, 221 Appleton St.•