The lobster fishery has been the one bright spot in Maine’s seafood industry for years — at least until last week.

On Feb. 18, the state Department of Marine Resources ordered a two-year shutdown of lobster and crab harvesting in a 7-square-mile region at the mouth of the Penobscot River. Mercury contamination from decades-old industrial pollution has reached high levels in the shellfish, and it should not be consumed, regulators say.

It’s still unclear who knew about these high levels and for how long, and how many pounds of lobster and crab were harvested and consumed in the meantime.

What should be obvious to everyone, however, is how devastating an event like this could be to one of the state’s most important industries and how even a small event could have huge impact on a valuable resource.

Too often, environmental regulation is cast as an impediment to economic growth, and businesspeople and their supporters in government insist that regulators can do the most good by simply getting out of the way.

That is not what was needed here.

Maine’s economy is based on its natural resources, which are not limited to seafood such as lobster and crab or produce such as blueberries and potatoes. Maine sells its environment when it attracts tourists and other visitors who employ tens of thousands of Mainers all around the state, all year long.

The notion that Maine’s lobsters could be unsafe to eat, or that Maine air and water might not be clean, could be devastating to those industries.

Far from being bad for business, environmental regulation is essential for business to succeed, especially the kinds of businesses that Maine depends on.

Unfortunately, ensuring that justice is done is a slow process. Mallinckrodt LLC, the company responsible for the mercury spilled by HoltraChem Manufacturing, is fighting in court to limit its role in the watershed’s cleanup. The court should make sure that the company is held responsible, but prevention would have been better.

The next time we hear a politician complain about too much regulation, we should all remember this situation and reflect about how much trouble good regulation can avoid.