We often hear complaints about the state’s environmental agency, mostly because people, especially business owners, think it goes too far in regulating activities that affect land, forests, wildlife or water.

That’s why we were surprised to learn last week that the state Department of Environmental Conservation backed off on enforcing a cleanup of a massive gasoline spill at the former Mobil Station at 29 Chestnut St. in Cooperstown.

In fact, the DEC admitted that contamination levels did not meet state standards and that it allowed the cleanup to be halted anyway _ despite the proximity of the spill to Otsego Lake, Cooperstown’s source of drinking water.

Ordinarily, when it comes to lakes and drinking water, the DEC is a tough guy.

The spill from corroded underground gasoline tanks was detected in 1987 at the former Mobil station, which is less than one-third of a mile from the lake.

DEC closed its books on the spill and cleanup in April 2006 even though pollution at one spot at the former gas station, now a parking lot, was still hundreds of times above state standards, according to one of the agency’s own spills investigators.

Even ExxonMobil, notorious for its gigantic Alaska oil spill in 1989, pointed a finger at DEC, saying it only ceased the cleanup operation because the state agency said enough work had been done.

The major contamination culprits are the gasoline components BTEX, which is benzene, toluene, ethylbenzene and xylene, and the additive MTBE, which stands for methyl tertiary butyl ether.

Those chemicals have been found by research to be carcinogenic or harmful to humans in other ways.

And to think that it’s been more than a year since the cleanup was halted. It’s likely most local residents thought the job was completed and the contamination had been removed; and that the groundwater was safe.

But Win McIntyre, Cooperstown’s watershed consultant and former head of engineering for Procter & Gamble, apparently knew better.

``I don’t think they did a good job,’’ he said last week. ``I think they need to go back in there and re-establish the cleanup operation.’’

That’s because he says he believes that groundwater in the area of the spill moves toward Otsego Lake. He says he thinks there is a risk of MTBE entering the lake but, fortunately, probably not in concentrations that would compromise drinking water.

Of course, the DEC spill records had the contamination located about two miles from the lake, not the third of a mile documented by experts. No wonder our state’s ``environmental watchdog’’ concluded that pollution is unlikely to move off-site and threaten water supplies and will naturally degrade over time.

But can we trust an agency that doesn’t know how far contamination is from a drinking-water source and prematurely shut down a cleanup operation?

That’s what Cooperstown residents have to be asking themselves.