A pesticide is an agent used to repel any microorganism, plant, insect, or animal that is harmful in some way to humans. These chemical combinations are not only common in environmental applications, such as to control weeds and destructive insects in our yards and crop fields, but are also widely used in households. Some examples of everyday pesticide products would be mosquito repellant, cockroach and ant sprays/traps, kitchen and bathroom disinfectants, rat poison, flea and tick collars and powders for pets, mold and mildew cleaners, and some swimming pool treatments.

Because these substances are in effect poisonous to living organisms, some pesticides have been shown to have dangerous and long-lasting consequences for people who come into contact with them. Pesticides, including fungicides and herbicides, are widely used in agriculture and lawn care, in our homes and schools, and on the job.