You may have heard of the new genetically engineered Simplot potato. It was made with a new GE technology called RNAi (RNA interference), a technology for which many important gaps remain in our understanding.

In fact, when the U.S. Environmental Protection Agency (EPA) recently asked a panel of independent scientists for advice about this technology, which alters the function of genes in the plant, the scientists wrote a detailed report [PDF] that warned the agency of risks that could sometimes result in harm.* And, they noted that current regulations were not well designed to address these risks.

But those concerns didn’t keep the U.S. Department of Agriculture (USDA)—the agency with the greatest responsibility to prevent environmental impacts of GE plants—from approving the Simplot potato. Nor have they deterred the USDA from charging ahead with allowing the companies making potatoes that have some of the same properties as Simplot’s, made through a process of “genome editing,” to avoid environmental regulation altogether simply because they do not contain plant pest genes or otherwise fit USDA’s narrow definition of a “plant pest.”

USDA’s regulatory processes have already failed to prevent hundreds of millions of pounds of additional herbicide use [PDF] that have arisen from the irresponsible use of glyphosate (or “Roundup”) on GE crops nor the tens of millions of acres of glyphosate-resistant weeds that have resulted. Nor has it prevented the repeated contamination of traditional crops, costing farmers billions of dollars in lost markets. But now it has become clear that many of the companies producing GE crops are evading environmental regulation entirely, with the agency’s blessings.

One good example is Scotts, the lawn product company, which wrote to the USDA several years ago asking whether it needed to regulate a Roundup-resistant GE Kentucky bluegrass. Scotts claimed that because it did not involve plant pests in developing the grass, it should be absolved from regulation—and USDA agreed.

In the early days of genetic engineering, the large majority of GE crops used plant pest genes or processes. But that is no longer the case. The large majority of potentially useful, and possibly harmful, genes—whether from other plants, microbes, or animals—no longer come from pests. And many kinds of harm that GE crops may cause, like resistant weeds or the loss of monarch butterflies, are not captured by USDA’s current definition of “plant pest” harm.

Meanwhile, the trickle of GE crops escaping regulation is threatening to become a flood. A look at the docket of requests to skip regulation shows that since USDA absolved Scotts’ GE bluegrass of regulation in 2011, 18 other crops and organisms have been declared unregulated, including six in the last two months alone.

As recently as January 13, GE Loblolly pine, a native tree important in ecosystems throughout the southeast, was given a free pass—even though its possible impacts on the environment and the many species that depend on the tree is still largely unknown.

Many of these GE crops are not fundamentally different, from a risk perspective, than crops that were previously regulated and that have been responsible for serious environmental impacts. For example, Scotts’ GE Kentucky bluegrass, and other grasses like it that have evaded regulation, presents similar risks as other Roundup-resistant crops: They might create more resistant weeds and result in more herbicide use. And this Bluegrass could be worse in some ways, since it is known to be invasive in some environments.

Genes that may increase the competitiveness of plants like grasses or trees– for example, genes for drought tolerance or faster growth–are enticing to seed, timber, or biofuels companies. But they may result in crowding out other plants, as the National Academy of Sciences warned in a 2004 report. Many crops in the U.S. also have wild relatives that are serious weeds, and that will pick up engineered genes from crop pollen. These include wheat (jointed goatgrass), lettuce (prickly lettuce), rice (red rice), and sorghum (the notorious Johnsons grass), to name a few. Meanwhile, GE sorghum developed by Ceres, Inc. for increased yield and other properties, was freed from regulation in 2014.

It would be one thing if the actual regulation USDA does undertake was more effective. But as it is, this new regulatory vacuum could make a dire situation worse.

USDA has been regulating GE plants for environmental impact since the 1980s. And while the regulation has come under substantial criticism from the National Academy of Sciences, the Government Accountability Office, numerous Federal Courts, and others, USDA has generally ignored recommendations to improve rigor and monitor crops after commercialization.

The USDA’s chosen interpretation of the law it is charged with applying to GE organism oversight has also been irresponsibly narrow, leading to weak regulation that ignores many types of actual and potential environmental harm from these crops, such as the next generation of herbicide resistant crops [PDF] which are immune to older, more risky herbicides like 2,4-D, and will likely further increase resistant weeds, and herbicide use by several fold. USDA has already approved several of these crops.

The agronomic and environmental harms of genetically engineered crops can be indirect, such as competition from resistant weeds or the loss of pollinators, and other animals and insects, loss of soil fertility, associated pesticide impacts, transgenic contamination effects, and so on. Notable already is the drastic reduction of monarch butterflies due to the near-elimination of milkweeds in the Midwest—relied on for food by monarch caterpillars—by glyphosate herbicides used on GE crops. Yet the agency has chosen to ignore these impacts.

I use the word “chosen” intentionally. As I have written about before, the USDA has blandly claimed that it does not have authority to regulate indirect harms from GE crops, as if it were out of its hands. But in fact, the agency is deliberately thumbing its nose at the public by refusing to enact the regulations it has been authorized to use. And so are the seed and pesticide companies that are simultaneously skirting those regulations and lobbying to keep them weak.

You see, 15 years ago, Congress passed in the Plant Protection Act (PPA) of 2000 [PDF], which provides for regulation of possible direct, indirect, environmental, economic, and public health harm from GE crops. But the agency has refused to write new regulations to implement the PPA.

If enacted sensibly, regulation under the PPA would allow USDA to evaluate all the risks I’ve discussed above. But given the agency’s intransigence, that might require legal action as well as state action and public pressure, to force the agency to do what the law and responsible governance requires.

*The SAP was about pesticidal RNAi, but the principles apply to RNAi altered plants generally.