Want to know what’s in store for neighborhoods near Brooklyn’s Gowanus Canal, now that federal eco-crats have dropped a giant tarp over the gunky waterway? Ask the folks trying to get something built at Ground Zero.

There, the Environmental Protection Agency — which recently designated the Gowanus a Superfund toxic-cleanup site — held up deconstruction at the 9/11-scarred Deutsche Bank building for years without a whit of evidence that the process was harming anyone’s health.

The agency ordered the entire structure scrubbed until not a dime-sized smudge of dirt remained — causing delays that stalled work at the entire site.

So imagine the trouble the EPA can cause when there actually is pollution to be cleaned up.

Which is inarguably the case at the Gowanus Canal.

But the city already had its own cleanup plan — one that required neither EPA bullying and incompetence nor the development stigma that comes from the Superfund label.

Already, developer Toll Bros. has announced that it’s pulling the plug on its plan to build 450 units of housing along the canal, citing its inability to find financing and insurance at a Superfund site.

The weak economy may have had something to do with that, too, but the EPA ruling was surely a nail in the coffin.

That’s entirely understandable: While the agency says the project will take only 10 to 12 years, it first intends to sue everyone it thinks helped cause the pollution — potentially causing years of delays.

Moreover, who knows what kind of virgin-wetlands standard it’ll demand before declaring the canal “clean”?

The EPA, after all, answers to no one but itself.

Moreover, the commissar at the top of this particular food chain, Northeast Regional Administrator Judith Enck, surely can’t be expected to act reasonably.

Enck was Gov. Paterson’s all-powerful environmental czar last year when the state asked the EPA to take over Gowanus — without so much as telling the city first.

Now the state Department of Environmental Conservation won’t even talk about the Superfund designation — referring all questions to Enck.

What a power grab.

Power gained, of course, is never willingly relinquished.

So look for the EPA to rule — and misrule — Gowanus for decades into the future. All while Brooklyn suffers.