What is a notable characteristic of carbamate insecticides?

Carbamate insecticides are noteworthy because many of them were indeed removed from the market in the 1990s due to concerns about their environmental impact and potential harm to human health. This led to increased regulations and, in many cases, the phased-out use of these chemicals. The removal was part of a broader movement towards safer pest control chemicals and practices, reflecting growing awareness and concern over the toxic effects of various pesticides.

The other options present a different understanding of carbamate insecticides. While they have seen regulated use, stating that they were predominantly approved in the 2020s overlooks their historical context. Similarly, claiming that they have no toxic effects on humans misrepresents their safety profile, as many carbamate compounds do indeed pose health risks under certain exposure scenarios. Lastly, although some carbamate insecticides can be used in agricultural settings, they are not restricted solely to that area, as they also find applications in residential pest control, illustrating their versatility beyond just agricultural use.