(07-29) 04:00 PDT Sacramento -- After a flurry of locally approved measures that ban the farming of genetically engineered crops, California lawmakers are considering a late-session push to prevent more counties from passing prohibitions.

The proposed legislation is a response to recent action taken by Marin, Mendocino, Santa Cruz and Trinity counties, which banned genetically engineered crops through ballot measures or government ordinances.

Other counties have taken action in favor of genetically engineered crops. Kings, Kern, Fresno, San Benito and San Diego counties have passed resolutions declaring support for crops derived through biotechnology.

"We are concerned that if we decide county by county that we can't use biotechnology, it'll really tie our hands," said Cynthia Cory, director of environmental affairs at the California Farm Bureau Federation. "California farmers will miss a great opportunity."

With California divided in its opinions about genetically engineered foods, state Sen. Dean Florez, D-Shafter (Kern County), has introduced a bill that would stop counties from regulating genetically altered crops. While the four counties that already have bans in place would be exempt, California's remaining 54 counties would be required to look to the state for regulation of the industry.

But because the state doesn't have a policy on genetically engineered crops, opponents say, the bill would leave Californians dependent on federal regulations that tend to rely on the industry for most product safety guarantees.

Jeffrey Smith, founder of the Institute for Responsible Technology, says federal regulations are inadequate even though an Assembly Committee on Agriculture analysis of the bill says the federal government already regulates genetically engineered foods more heavily than other foods.

"Biotechnology seed ... already receives much greater scrutiny than any other conventional agriculture product," the committee's analysis says. "In total, the regulatory scheme that governs the safe use of biotechnology comprises between 10 and 15 years of governmental research and oversight."

Charles Margulis of the Center for Food Safety says the research and oversight provided by the federal government are insufficient, given the potential dangers of biotechnology. Genetically engineered foods could potentially cause unnatural allergies, introduce high levels of toxicity in the human diet and create antibiotic resistance, he said.

"The general risk is that you're introducing proteins from genes that have never been in the human diet before," Margulis said.

But supporters of the legislation, SB1056, say genetically engineered foods are just as safe as organic products.

The farm bureau wants California's farmers to be able to capitalize on the advantages of biotechnology without local government interference. Genetically engineered seeds are often associated with increased crop productivity, better-looking foods and crop resilience.

Cory and others also argue that varying standards throughout the state will become problematic for California's farmers, especially if more counties decide to ban genetically engineered crops.

But opponents say the bill would make organic farmers less competitive, burdening them with the added cost of protecting against contamination from neighboring genetically engineered crops.

"In the organic industry, many buyers will require the product to be tested and will reject the crop if the contamination exceeds their threshold," said Smith. "If a (genetically modified) crop contaminates an organic field, the organic farmer may lose investors or market" share.

Smith argues that because genetically engineered seeds are patented, organic growers also face legal trouble when their crops become contaminated.

"Organic growers are liable for contamination even if it's not their fault," he said. He cites a recent case in Canada, where an organic farmer was sued for patent infringement when genetically engineered seeds blew into his crops. The farmer was sued by Monsanto, the company that owned the rights to the seeds.

Organic farming is the fastest-growing segment of California's agriculture industry, according to the Department of Food and Agriculture. In 2005, organic farming made up 2.3 percent of total agriculture value, an increase from less than 1 percent in 1998.

Florez says his bill is "sponsored by all of agriculture," including Monsanto, a biotech company that sells 88 percent of the world's genetically engineered seeds. Monsanto has supported similar bills in 16 other states, contributing large amounts of money for campaigns to prevent counties from banning Monsanto's seeds.

Opponents of the bill question its pre-emptive nature.

"The state is pre-empting local governments from legislating about this issue while the state has no policy, which doesn't make sense," said Pete Price, a lobbyist who represents a number of the bill's opponents.

Florez says he is aware of the need for a state policy, and plans to work out a set of regulations that would be a fair compromise between farmers who grow genetically engineered crops and organic farmers.

The bill originally dealt with air quality in the San Joaquin Valley, but was drastically amended by the Assembly Committee on Agriculture. The bill is now headed to the full Assembly.