The nation's organic farmers are sounding the alarm after an Obama administration decision they say could destroy their supply chains and drastically limit the choices and availability of some popular consumer foods.
The Department of Agriculture decided last week to allow the widespread, unregulated use of genetically modified alfalfa, commonly known as hay, which is the primary feed for dairy cows and beef cattle across the country.
Opponents argue that he mutant crops, engineered to survive being sprayed with insecticide, could escape from their fields and eventually cross-pollinate with and contaminate neighboring organic crops. That could mean less organic feed for the organic cows that produce a range of organic products.
"Consumers don't eat [genetically modified] alfalfa, of course," said Michael Pollan, author of "The Omnivore's Dilemma," which examines the U.S. farming and food industry. "But it's the main feed for dairy cows. And organic milk, one of the most successful and popular organic foods, could be compromised if the organic cows eat non-organic feed."
Some environmental experts are also concerned that broader planting of herbicide-resistant crops, which are then doused with powerful chemicals, could expedite the spread of "superweeds," which are herbicide-resistant pests that force farmers to potentially use more toxic substances to root them out.
"This is a bad solution to a nonexistent problem," said Pollan, who noted more than 90 percent of alfalfa crops are grown without a herbicide.
Many organic farming advocates speculate that the new Roundup-ready alfalfa is an attempt by the crop's commercial producers -- Monsanto and Forage Genetics International -- to dominate the market and increase profits.
But Monsanto, the nation's leading producer of genetically modified seeds and popular herbicide Roundup, said Roundup-ready alfalfa has been welcomed by many farmers because it yields "healthier, faster-growing stands [plantings] and hay with fewer weeds in every bale."
The special seeds were first widely planted in 2005 on more than 250,000 acres before a court order in 2007 halted further planting until the USDA could review complaints by organic farming groups.
"Roundup-ready alfalfa is not expected to become more invasive in natural environments or have any different effect on critical habitat than traditional alfalfa," the USDA said in a statement explaining its decision. "In addition, the nutritional profiles of RR alfalfa and traditional alfalfa are not different (within normal cultivar variations); therefore animal nutrition is not expected to be different."
Agriculture Secretary Tom Vilsack said the agency has formed two advisory committees to evaluate the rollout of genetically modified alfalfa and ensure growers have access to non-modified seed if they want it.
"I see real progress here," New York University professor and food expert Marion Nestle wrote in the Atlantic earlier this month of the government's willingness to weigh regulation of alfalfa. "At least -- and at last -- USDA recognizes the threat of GM [genetically modified] agriculture to organic production."
But many critics were shocked that the agency didn't accommodate any of their concerns, including a possible rule requiring that altered crops not to be planted alongside organic ones.
"USDA has become a rogue agency in its regulation of biotech crops and its decision to appease the few companies who seek to benefit from this technology comes despite increasing evidence that GE [genetically engineered] alfalfa will threaten the rights of farmers and consumers, as well as damage the environment," said Andrew Kimbrell, executive director for the Center for Food Safety.
He said the group plans to sue.
Critics say the complete deregulation of genetically modified alfalfa stems from the Obama administration's recent push to reach out to the business community and take steps that are considered business-friendly.
Obama signed an executive order earlier this month to make clear the administration seeks to strike the right balance with regulations, neither "placing unreasonable burdens on business; burdens that have stifled innovation and have had a chilling effect on growth and jobs" nor failing to "protect the public interest."
The administration, the president wrote in a Wall Street Journal op-ed, is "making it our mission to root out regulations that conflict, that are not worth the cost, or that are just plain dumb."
Farmers already grow genetically modified soy beans, corn and cotton, among other crops, which are engineered to produce higher yield, thrive in adverse growing conditions and resist pesticides that kill weeds. Producers say the technology results in cheaper prices for consumers at grocery stores.
"Roundup-ready alfalfa is as safe as traditionally bred alfalfa," secretary Vilsack said Thursday. "All of the alfalfa production stakeholders involved in this issue have stressed their willingness to work together to find solutions."
But some Americans don't want to eat genetically modified foods for health or ethical reasons.
Organic foods have become big business, with producers reporting $26 billion in annual sales last year. While only 4 percent of U.S. agriculture involves organic products, the industry has posted double-digit growth in gross profits nearly every year for the past decade.
"The growth is there because this is what consumers are demanding. They want organic products," said Christine Bushway, executive director of the Organic Trade Association.
"If our supply chain gets disrupted by these genetically- modified crops and we can't supply the organic goods, then will severely hamper the choices for consumers."
ABC News' Brian Hartman contributed to this report.