It’s good to see that you know GMOs are subjected to government review, because some people believe there is no regulatory oversight of these crops.
I am not sure how the rumor got started that government oversight for GMOs is lax or nonexistent, because nothing could be further from the truth. These crops are subjected to more testing than any other new crop variety, and, as a result, we know more about this set of crops than any of the other crops that plant breeders have developed (and we've eaten!) over the past few centuries.
In the United States, GM crops are subjected to regulatory review by at least two, and sometimes three, federal agencies: the Food and Drug Administration (FDA), the U.S. Department of Agriculture (USDA) and the Environmental Protection Agency (EPA). FDA is responsible for assessing the safety of any GM crop used for food or animal feed, and USDA assesses the crop’s potential impacts on the environment and agriculture. If the GMO has been modified to provide resistance to pests that would like to eat the crop before we can―e.g., insects and plant pathogens―then EPA also assesses the environmental and food safety of the new substance produced by the plant that provides the pest-resistance trait. The most familiar examples of GM pest-resistant crops are Bt crops. These crops contain a gene from the bacteria Bacillus thuringiensis, which is the active ingredient in microbial sprays used by organic farmers and many home gardeners to control certain insect pests.
Federal agency review of information on a GM crop begins very early in the product development process, i.e., prior to the first field trials. Before the crop can move from the greenhouse to the field for testing, the developer must receive a thumbs-up from USDA, which, in turn, notifies the departments of agriculture in the states where the field tests will be planted. Around the same time, FDA or EPA (depending on the GM crop trait) is reviewing laboratory information on the safety and potential allergenicity of the protein encoded by the new gene. These early confirmations of the protein’s safety are performed just in case GM material (pollen or grain) enters the food supply unintentionally during the field trial stage. If you are interested in the sort of information developers provide for the these "early food safety evaluations," check out these FDA guidelines.
EPA asks for similar test results for proteins encoded by pest resistance genes. See, for example, pages 5–7 of this Biopesticides Registration Action Document. When you read that EPA has “exempted” a Bt protein, that means the protein has passed a battery of tests and has been shown not to cause harm when mice eat very large amounts of it. Therefore, there was no need for EPA to establish a “tolerance level “ for residues of the Bt protein in food/feed, as it does for chemical pesticides. The Bt protein is exempted from the requirement to establish a tolerance level; it is not exempted from the requirement for a safety review. For the scientific underpinnings of assessments of protein safety, see this report.
The field trial stage lasts a number of years, and every year, the crop developer needs an okay from USDA for the field trials. If 1) the crop has a pest-resistance trait and 2) the field trial is larger than 10 acres, then EPA must also approve it.
The field trials serve a number of important objectives. First of all, they let the developer know if the new gene works as intended and if the GM crop performs as well as comparable non-GM varieties under a range of growing conditions. Field trials also allow the developer to collect information that they will need for final regulatory approval. They study the crop’s potential environmental impacts, and they collect crop material from a number of locations and analyze it to ensure the GM crop has a nutritional and food safety profile that is comparable to that of a non-GM comparator.
You are probably interested in the specific types of information reviewed by the agencies to evaluate a GM crop’s safety for food, feed and the environment.
With respect to potential environmental impacts, they evaluate potential negative effects on a variety of potential “nontarget organisms” (e.g., fish, birds, honeybees, ladybugs, parasitic wasps, lacewings, springtails, aquatic insects and earthworms), the soil microbial community, soil quality, biological diversity and populations of endangered or threatened species. They also look at the possibility of gene flow to wild relatives and, if gene flow is possible, its potential environmental impacts. They study how rapidly the plants degrade in the environment to determine possible exposure levels and evaluate the crop’s potential for weediness. They also look at how the GM crop may affect the use of agricultural chemicals.
The specific environmental factors the agencies review vary a bit depending on the nature of the crop. You can see the types of environmental information that USDA and EPA review by going to their websites and looking at the actual documents. You can find general information on EPA’s regulation of GM crops here.
You can find specific information on the GM products EPA has approved here. Click on any current or previously registered product to see the test results and EPA’s evaluation.
With respect to USDA, the tables here have links to USDA’s environmental assessments for every product that has been USDA approved, as well as information provided by the developer (in the column labeled “Petition”).
Finally, in addition to an early assessment of the safety of the protein encoded by the introduced gene, FDA evaluates the safety and nutritional value of the whole crop. It looks at information on all of the biochemical factors related to nutritional value, such as fiber content and total amount of protein, carbohydrates and fats, as well as the amounts of each amino acid, fatty acids, vitamins and minerals. It also measures components in food that pose safety considerations. For example, some crops naturally have chemicals (antinutrients) that are not good for us if they occur in high amounts. For example, potatoes have solanine, and soybeans produce substances that prevent nutrient uptake. Crop developers must show that the amounts of natural toxins and antinutrients have not been increased accidentally through by the genetic modification. The same is true for allergenicity. In addition to assessing the potential allergenicity of the new protein, developers must verify that the genetic modification did not inadvertently increase the amount of known or suspected allergens in foods that are known to allergens to some people, such as soybeans. FDA’s review process is described here and here.
This data collection is an extensive, expensive and thorough process—estimates are that it takes over 13 years from initial work in the lab to get a new GM crop product to the market, with at least six years dedicated to safety-data collection and regulatory review. In addition, the review process described above for the United States is repeated many times over for GM commodity crops that wind up being exported and used globally. By the time most new GM crops are made available to farmers, the product will have been reviewed by dozens of regulatory agencies around the world and will have received input from hundreds of independent expert reviewers.
So, as you can see, by any measure it is not “easy” to get GM crops approved and on the market.