By Carey Gillam

Government testing for residues of glyphosate has been put on hold, slowing the U.S. Food and Drug Administration's (FDA) first-ever endeavor to get a handle on just how much of the controversial chemical is making its way into U.S. foods.

Getting solid data on glyphosate's presence in the American food supply is more important than ever as the EPA finalizes a risk assessment for glyphosate and tries to determine if any limits should be put on the future use of the herbicide.

The FDA, the nation's chief food safety regulator, launched what it calls a "special assignment" earlier this year to analyze certain foods for residues of the weed killer after the agency was criticized by the U.S. Government Accountability Office for failing to include glyphosate in annual testing programs that look for many less-used pesticides. Glyphosate is the most widely used herbicide in the world and is the key ingredient in Monsanto's flagship Roundup.

Glyphosate is under particular scrutiny after the World Health Organization's cancer experts declared last year that the chemical is a probable human carcinogen. Several private groups and nonprofits have been doing their own testing and have been finding glyphosate residues in varying levels in a range of foods, raising consumer concerns about the pesticide's presence the American diet.

The FDA's residue testing for glyphosate was combined with a broader herbicides analysis program the agency set in motion in February of this year. But the glyphosate testing has been particularly challenging for the FDA. The agency was finally forced to put the glyphosate residue testing part of the work plan on hold amid confusion, disagreement and difficulties with establishing a standard methodology to use across the agency's multiple U.S. laboratories, according to FDA sources. Equipment issues have also been a problem, with some labs citing a need for more sensitive instruments, sources at the FDA said.

FDA spokeswoman Megan McSeveney confirmed the testing suspension and said the agency is not sure when it will resume.

"As testing for glyphosate will expand to several locations, we are currently working to ensure that the methods are validated for use in these labs. As soon as the validation is completed, testing for glyphosate will resume," she said. "We cannot speculate on timing at this point."

Alongside the testing for glyphosate, the FDA laboratories have also been analyzing foods for 2,4-D residues and other "acid herbicides," according to documents obtained from the FDA. The FDA's Office of Compliance explained that the need to start such testing was partly related to the cancer concerns about glyphosate and expectations for a sharp rise in the use of 2,4-D.

The FDA work detail calls for the examination of roughly 1,340 food samples, 82 percent domestic and 18 percent imported. The foods are to be collected from warehouse and retail stores only and are to include a variety of cereal grains, vegetables and non-flavored, whole milk and eggs. Documents obtained from the agency through the Freedom of Information Act show the agency has been testing corn, soybeans, wheat, barley, sugar beets, rice and even samples of yellow popcorn and "organic white popcorn."

McSeveney said glyphosate residues were only being analyzed for soy, corn, milk, eggs and popcorn, while the other foods are being tested for residues of other herbicides.

Earlier this year, one of the agency's senior chemists analyzed glyphosate residues in honey and oatmeal and reported his results to the agency. Some honey samples contained residue levels well over the limit allowed in the European Union. The U.S. has no legal tolerance for glyphosate in honey, though the U.S. Environmental Protection Agency (EPA) said recently it may set one because of the FDA findings. However, according to McSeveney, the results for honey and oatmeal are not considered to be a part of the official assignment.

With the testing on hold, it is not clear when the agency might have final results on the glyphosate residue analysis. McSeveney said preliminary results showed no violations of legal tolerance levels allowed for glyphosate in the foods tested. She did not provide details on what, if any, levels of residue were found. Tolerance levels are set by the EPA for a variety of pesticides expected to be found in foods. When residue levels are detected above the tolerance levels, enforcement action can be taken against the food producer.

Monsanto said earlier this year that no data has ever indicated residue levels of more than a fraction of allowable levels and it is confident FDA testing will reaffirm the safety of its herbicide.

Though FDA annually tests domestic and imported foods for residues of other pesticides, it never tested for glyphosate before. It has not routinely tested for 2,4-D either, a fact also criticized by the U.S. Government Accountability Office. Unlike glyphosate, however, there has been some monitoring of 2,4-D residues in selected food items in the past. That monitoring showed only very low levels of 2,4-D—less than 5 parts per billion in ready-to-eat foods, according to the FDA.

The FDA testing for 2,4-D residues comes as the use of 2,4-D with food crops is expected to start increasing due to the commercialization of new formulated herbicide products that combine glyphosate with 2.4-D. These new herbicide products are designed to be used on new herbicide-tolerant crops. Safety questions have been raised about the combination. But the EPA just gave a green light Nov. 1 to a Dow AgroSciences' herbicide combination of glyphosate and 2,4-D. The new products are intended to counter widespread weed resistance to glyphosate.

The agrichemical industry asserts that residues of glyphosate, 2,4-D and the array of other chemicals used in modern-day agriculture do not pose a danger to human health, but the lack of testing to determine actual residue levels of some of the most-used chemicals, has been troubling to many consumer groups.

Getting solid data on glyphosate's presence in the American food supply is more important than ever as the EPA finalizes a risk assessment for glyphosate and tries to determine if any limits should be put on the future use of the herbicide. The FDA work covers only a few foods, but is a long-needed, good first step. Consumers can only hope the testing resumes soon.