Maine will soon become the last state in the nation to let farmers grow corn that’s genetically engineered to be toxic to pests.

The state’s “I Lead” motto notwithstanding, this is one of those cases when being last has its advantages.

A new federal study that made news this week found the genetically engineered variety – called Bt corn – may get into streams and kill insects that provide food for fish.

Opinions about what to do with that knowledge range from ignoring it to reversing course and keeping Maine a Bt-free zone. At the very least, it’s one more kernel of information for Maine regulators to chew on as they take up the state’s first set of rules for growing Bt corn.

Bt corn is engineered to produce a toxin – bacillus thuringiensis – that protects the crop against European corn borers. Bt is a natural toxin and can also be sprayed on crops, but it degrades quickly and doesn’t work for long.

Corn that’s sprayed with Bt is still considered organic and can be used as feed on organic dairy farms. The genetically engineered variety, on the other hand, is, officially, not organic.

Bt corn now represents about 35 percent of the corn acreage in the United States. Much of that gets eaten by livestock. But, if you’ve eaten corn on the cob anyplace other than in Maine, or even just outside of corn season here, you’ve probably eaten Bt corn. Swallowed any corn chips? Canned corn? Popcorn? Then you’ve eaten the genetically engineered variety.

Maine’s Board of Pesticide Control rejected the use of Bt corn a decade ago when its use was being phased in everywhere else around the country. Last year, however, seed manufacturers and farmers went back to the board and got permission to grow Bt field corn for feed.

So far no one has asked for permission to grow Bt sweet corn to sell at farm stands and supermarkets. This is Maine, after all. One new thing at a time.

The board opened the Bt door despite a range of objections, including the potential for human health and environmental effects. Opponents also argued that the state’s farmers have developed a valuable competitive advantage simply because of Maine’s reputation as the lone organic holdout.

Board members ultimately sided with those who said the engineered corn has now been shown to be safe for people and the environment. But they also decided not to blindly follow the other states.

Maine’s proposed rules define Bt corn as a regulated pesticide, a step beyond federal rules. They also would require farmers to be licensed to plant Bt corn and take precautions not required elsewhere.

The rules are the focus of what is expected to be a big Board of Pesticide Control meeting Nov. 16 in Waterville. That meeting got even bigger this week when word of the National Science Foundation study spread through the state.

The report, which was published last month, said pollen and pieces of corn plants can drift or get washed into streams, a possibility that had not been studied by federal regulators before. The toxin is eaten by caddisflies, which happen to be a close relative of corn borers as well as a favorite food of fish and amphibians.

That report provides some late ammunition for those who hope the board changes its mind and bans Bt corn, or at least adopts strict rules about how its used.

Either way, the state has the advantage of going slow.

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