Pesticides are chemicals used to kill, control, or repel pests. Target pests can include insects, worms, weeds, mollusks, birds, mammals, fish, and plant pathogens. There are many types of pesticides with diverse chemical structures that are formulated into many different products with human toxicity. The inert constituents and solvents in pesticide products can also be toxic, sometimes more toxic than the pesticide. In the United States, there are more than 1000 individual pesticides marketed in approximately 20,000 products. The complexity and diversity of pesticide products necessitate that they be specifically identified in exposure situations. This can be difficult because pesticides are often transferred from their original packaging to other containers that are smaller and more convenient to use. Pesticide products are heavily regulated by federal and local laws that specify how they can be marketed, who can purchase them, and how they must be used. Some examples of common pesticides are provided in Table 24.1.