Dairy farmer Dennis Leonardi, who describes himself as a "taxpayer and law-abiding citizen," will soon harvest the genetically engineered corn he grows to feed his 400 cows.

But a measure on the Nov. 2 ballot in Humboldt County would make Leonardi's harvest illegal - and possibly send him or anyone else growing such crops to jail.

"This is a measure that has gone over the edge," said Leonardi, a third-generation Ferndale farmer. "It's absolutely ridiculous to make criminals out of farmers."

Three other California counties are attempting to pass similar measures on Nov. 2 that would ban genetically engineered plants and animals from their borders. Supporters of the ban argue that biotech crops poses a risk to human health and the environment - contentions the industry strongly disputes.

The ballot measures in Butte, Marin and San Luis Obispo counties don't criminalize genetically engineered agriculture like Humboldt County is attempting to do. Those three counties have followed the lead of Mendocino County, which passed the nation's first ban in March, providing for small fines and the destruction of the biotech crops.

Organizers in several more California counties are collecting signatures in hopes of qualifying their own anti-biotech measures in early 2005. Activists in Hawaii, Vermont and elsewhere are also circulating local petitions and urging politicians to pass similar legislation.

Critics of biotech crops say the bans are needed to ensure that farms that grow conventional and organic crops aren't inadvertently cross-pollinated by biotech varieties. So-called "gene flow" is an increasing concern among organic farmers, who fear such cross-pollination could ruin their crops.

Consumers in Japan, Europe and elsewhere demand all their crops are grown conventionally. Farmers who can't make those guarantees risk losing those markets.

Still, the biotech industry argues such county measures are bad public policy because it's already tightly regulated by the federal government and that local laws will create an impossible hodgepodge of red tape.

"Farmers should not be denied the right to use this technology if they choose," said Lisa Dry, a spokeswoman for the Washington D.C.-based Biotechnology Industry Organization. "To have imprisonment for growing genetically modified crops is wacky."

Lawyers and law enforcement officials also question whether the measure can ever be enacted with the imprisonment provision.

"Our position is that it is clearly a violation of the state and federal constitutions," said Humboldt County District Attorney Paul Gallegos.

Even some backers of the Humboldt County measure concede that the punishment proposed is too extreme. But they argue that the measure's intent is still sound and that any offending language can be fixed after the election.

"We are talking to lawyers," said Humboldt campaign co-chair Martha Devine. "I believe the measure can still go forward."

The proposed measures in Humboldt and Butte would, for the first time, directly affect farmers growing genetically engineered crops. The March vote in Mendocino County was seen largely as symbolic and a marketing boon to organic growers and vintners in the region because no genetically engineered crops are grown there.

Similarly, the board of supervisors in tiny Trinity County had their eyes on the region's salmon fishing when they enacted their own biotech ban.

No genetically engineered crops are grown in Marin and San Luis Obispo counties and organic farmers and vintners there hope to exploit their measures as marketing tools, especially in biotech-averse Europe.

But in Butte and Humboldt, dozens of dairy farmers like Leonardi grow corn that is genetically engineered to survive sprayings of Monsanto Co.'s popular weed killer Roundup. They say the engineered corn saves them money and eliminates the need to use a weed killer more toxic than Roundup.

Leonardi and his fellow farmers are offended that the Humboldt measure accuses them of criminal behavior and activists inserted language that could have him arrested.

"They didn't bother to come talk to us. They didn't look for any alternatives," Leonardi said. "Most of us are family farmers. We have small operations we are active in the community where we work. I'm really disappointed."