Large quantities of a number of chemicals are produced on a continuing basis by several industries, and the impact of only a small fraction of them both on nature and on human health is completely understood at this time. The major industries that contribute to the production of chemical compounds and waste are the petrochemical (fuels and monomers), agrochemical (pesticides, fertilizers), chemical (paint, explosives), electronics (conductors, resist materials), textile (dyes, fixatives), paper (pulp, bleaches), and pharmaceutical and medical (drugs) industries.