Organic proponents like to make a big deal over farming without synthetic pesticides and fertilizers and have tried to show that not using these chemicals leads to healthier and safer food. Regardless of whether there’s any scientific basis for health or safety benefits, however (and there’s not, say the most widely accepted meta-study, by Stanford University scientists), one thing that the organic industry has going for it are regulations for certifying what pesticide residues are prohibited. But in reality the US Department of Agriculture does little to enforce the rules and that gives reason to question whether any specific food labelled certified organic food was really produced without prohibited substances.

In 2012, the USDA’s National Organic Program released the results of an audit of organic foods in the United States. At first, the findings looked pretty good for organic farmers. After testing 571 samples of produce for 200 conventional pesticides, fully 96 percent were in compliance with USDA organic regulations. However, a closer look at those regulations shows that the USDA allowed pesticide residues below tolerance levels set by the EPA. When you take the 4 percent of organic produce that violated USDA (and EPA) rules, you then have to add pesticide residues that were indeed on the sample, but below EPA tolerances, which are set up for safety reasons, not for organic industry purity belief systems. When added up, this means that 43 percent of organic produce had prohibited pesticides, in some amount.

The USDA pointed to accidental drift of pesticides as the reason. But to former organic farm inspector and current advisor to the Heartland Institute Mischa Popoff, that’s unlikely. “Any organic farm has a 25-foot buffer,” he said. “So every pace you take reduces any drifting pesticide residue by a factor of 10. So, that 43 percent cannot possibly come from drifting over another farm.” In fact, a University of Nebraska guideline for pesticide application shows how quickly pesticide sprays fall to the ground, depending on droplet size.

Inspect standing fields

Popoff says that the USDA and Canadian agricultural officials need to do what he was never able to do as an inspector—test standing crops in the field. Currently, the USDA’s National Organic Program has pushed for certifiers to test end products, consisting of fruits, vegetables and other organic products that already have been harvested. “But you need to inspect a farm when the crop is standing,” he said. “That’s when an inspector can say, ‘wait, that doesn’t look right. Or, your yield is much too high.’”

Current regulations depend on a group of third-party companies that act as certifiers, carrying out the USDA organic rules on the agency’s behalf. Certifiers will charge the farmer a royalty fee between 1.5 percent and 3 percent of the farm’s receipts and as much as $2,000 for inspections. And nearly all the time, an inspection from a certifier will consist of an interview with the farmers and a review of the copious paperwork documenting the organic farm’s activities. “It’s an honor-based system. There’s no actual testing at the farm, and you’re just reviewing paperwork that says, yes, the farmer avoided pesticides,” Popoff said.

Without such testing, there is no way to determine whether an organic farmer is cheating, or heavy amounts of pesticides did indeed waft their way onto organic plots. Popoff recalled that during his last year as a USDA-certifier inspector, he tried to train his colleagues to inspect samples. This effort was met with significant resistance from farmers as well as government officials, several of whom told him “you’re going to destroy the organic industry,” and that “we have everything to lose and nothing to gain from field testing.”

A recent rule change from USDA appears to underscore the fact that certifiers aren’t doing much testing, either of samples or of standing crops. The new rules, finalized in 2013, require organic certifiers to “test samples from at least 5 percent of the operations they certify on an annual basis.” While the law has always required some kind of sample testing, it’s been up to “the discretion of the certifier.” The original attempts for rule-changing included spot testing of fields, Popoff has written. But under the current rules and considering that the certifier is paid by the farmer and has no real incentive to get tough on its customers, there’s not much room for rigor.

Organic industry to the rescue?

One surprising source of pressure for more testing—or at least enforcement—is coming from supporters of organic food. The Cornucopia Institute, a Wisconsin-based nonprofit, recently sent photos of a certified organic farm in Texas that the group alleged was illegally keeping cows and other livestock indoors—on the surface, a violation of organic farming rules. But the understaffed USDA declined to investigate. Online supplement sales maven and anti-GMO activist Joe Mercola has warned that organics sold by the national Whole Foods grocery chain have a 50/50 chance of not being organic, despite the label.

As part of the USDA’s funding for its National Organic Program, money is set aside for enforcement. The agency gets about 200 complaints every year from people who think that organic food actually isn’t. In 2013, just 19 farmers or food companies paid $87,000 for misusing the organic label. While the USDA says it’s stepping up its game, some cases show how widespread fraud can be, even from a single supplier:

Kenneth Nelson, from Bakersfield, California, pleaded guilty to fraudulently selling more than $40 million of allegedly organic fertilizer to farmers between 2003 and 2009. It turned out his “organic” product was made using aqueous ammonia and ammonium sulfate. How was he caught? County environmental health inspectors discovered the chemicals at the site, and called in a raid.

In Oregon, Harold Chase pleaded guilty to fraud for selling more than 4.2 million pounds of corn that had been labeled as organically grown. Chase was actually buying conventionally grown corn, labeling it organic and selling the product to Oregon organic livestock ranchers.

These cases illustrate that certification fraud can extend far beyond one farm. And without any type of testing while growing and planting are going on, it is difficult to identify the culprit.

Andrew Porterfield is a writer, editor and communications consultant for academic institutions, companies and non-profits in the life sciences. He is based in Camarillo, California. Follow@AMPorterfield on Twitter.