Organochlorine pesticides are effective against a variety of insects. These chemicals were introduced in the 1940s, but EPA banned many of the uses of these chemicals during the 1970s and 1980s. They are used rarely in the United States today because of their environmental persistence, but some continue to be used worldwide. They enter the environment from application, disposal of contaminated wastes into landfills, emissions from waste incinerators, and releases from manufacturing plants that produce these chemicals. Like PCBs, they bioconcentrate in fish and other seafood, and are found at higher concentrations in fatty foods.