In the US, all materials intended for sale and use as pesticides must be registered with the EPA. The process may be long, complex and expensive. It requires studies to be performed that indicate whether the material is effective against the intended pest and safe to use. During the registration process, a pesticide label is created which contains directions for the proper use of the material. Use inconsistent with the label is illegal and considered pesticide misuse.

Some pesticides are considered too hazardous for sale to the general public and are designated restricted use pesticides. Only certified applicators, who have passed an examination, may purchase or supervise the application of restricted use pesticides. Records of sales and use are required to be maintained and may be audited by the EPA or other state or county agencies charged with the enforcement of pesticide laws and regulations.

"Read and follow label directions" is a phrase often quoted by extension agents, garden columnists and others teaching about pesticides. This is not merely good advice; it is the law, at least in the USA. Similar laws exist in much of the rest of the world. The Federal Insecticide, Fungicide, and Rodenticide Act of 1972 (FIFRA) set up the current system of pesticide regulations. It was amended somewhat by the Food Quality Protection Act of 1996. Its purpose is to make pesticide manufacture, distribution and use as safe as possible. The most important points for users to understand are these: it is a violation to apply any pesticide in a manner not in accordance with the label for that pesticide, and it is a crime to do so intentionally.

Cite: Wikipedia