Military spending can do great things for communities. It brings jobs, stimulates the housing market and injects lots of cash into local economies. This year’s hand-wringing over threats to close facilities in Brunswick, Limestone and Kittery is evidence of the obvious: the departure of the military from those communities would be a wrenching experience for the locals who are left behind.

But defense installations can also be something less than a blessing, particularly after they are closed. The Pentagon has a dismal environmental record, and while some cleanup costs are borne by the federal government when a base shuts down, the prospect of cleaning up spills and contamination dating back for years can be daunting and very expensive, if it’s possible to clean up at all. At the centuries-old Portsmouth Naval Shipyard, for example, it’s a sure bet that contamination will prevent the re-use of some parts of the complex for years to come.

Base closings mean costs and benefits of many kinds. In Winter Harbor, where the Navy shut down a communications base in 2002, the town received a windfall in the form of houses in the village it could actually sell. Through a nonprofit corporation set up for the purpose (see page 1) the houses were sold and the town made a profit. On the cost side for a time at least, Winter Harbor found itself saddled with a school built for 180 students, but with only 27 kids to fill it. (That problem was solved when neighboring Gouldsboro suddenly needed school space due to the discovery of mold in its aging building and Winter Harbor was able to help out.) The number of jobs in town dropped drastically when the base closed, but then rebounded some as the Navy contracted for certain services and the economy strengthened.

A second new nonprofit organization, set up by the National Park Service and the Defense Department, is putting together a science education center in some of the former Navy buildings in Winter Harbor.

Corea, on the other side of the Schoodic Peninsula from Winter Harbor, suffered when the Navy closed a communications facility there, leaving behind a couple of large buildings. The buildings could become part of a halibut farm.

A benefit often touted by the Pentagon when it proposes to close a base is the opportunity to re-develop land and facilities for civilian purposes. Evidence to support this claim can be found in Bangor, where the former Dow Air Force Base was long ago recycled for a variety of non-military purposes including a community college and numerous businesses. But old Dow Field, right next to Bangor and its big airport, is well suited for such uses. Other bases, such as Brunswick Naval Air Station (on this year’s closing list) might offer recycling possibilities too, but so far the Navy has said it wants to keep the land there, meaning the local communities will take an economic hit with little possibility they’ll gain anything.

A base closing can hurt a community by removing a substantial part of the population, or it can help it by opening up closed areas to new development. There can be environmental benefits. The real effects of closings on communities, however, are subtle and can’t be known for years.

One question we’ll be left with, once the closing list is final, is how much money the Pentagon will actually save. Cleanups, the cost of re-aligning military units to other parts of the country, the loss of experienced workforces and other disruptions could cut substantially into the savings. It’s not that the Defense Department shouldn’t try to be more efficient or adapt to changing conditions — it should, of course — but whether the disruptions will really improve the bottom line. In the debate over base closing that has already begun, who’s got the right answers is anybody’s guess.