One of the most common images on the internet when you start researching chemical use on farms is of people in hazmat suits with backpack sprayers. This image has been compared to aliens exploring unknown planets, astronaut’s space suits, deepwater diving gear, and many other things that imply surviving a harsh environment.
The correct term for these suits are Personal Protective Equipment (PPE). For all chemicals used in any industry, from scientific research to manufacturing to agriculture, the U.S. Environmental Protection Agency (EPA) has standards for what equipment is needed for all chemicals. These standards range from things as simple as having to wear close-toed shoes, to being as strict as chemical respirators and sealed suits. For most agricultural chemicals that farmers use in GM and in conventional crops, the average recommendation is long sleeves and pants, and avoiding direct spills onto the skin. For some insecticides, there are more advanced requirements such as disposable jumpsuits and basic respirators. It is this type of chemical that the people in the pictures like the one you’re referring to wear.
Most insecticides are relatively toxic to people as they affect us in the same way that they affect the insects that they are being applied to control. These chemicals also break down in the environment, typically within a week or less for most of them. Sunlight, exposure to air, and naturally-occurring microbes all work to break down chemicals in the environment, and do a very good job of it. The U.S. Department of Agriculture (USDA) has standards for allowable limits for all chemicals that we use, and it’s almost unheard of to have any detectable residue if the farmer has followed the label recommendations.
In short, hazmat suits are only recommended for a small portion of the chemicals that farmers might use, some of which are cleared for USDA organic production as well as application on GM and conventional crops. The safety requirements for any chemical are determined by the concentration of the chemical and how it interacts with the human body. This has nothing to do with the crop that is grown being GMO, organic, or somewhere in between. These protective measures are only required when handling concentrated levels of chemicals, which when applied correctly, will not be detectable in the crop when it is time to harvest it.