Dichlorodiphenyl-trichloroethane --  commonly known as DDT -- is a controversial insecticide.  It has served as both an aid and even more as a danger to public health.

Brought to the U.S. in the middle of the 1940s, DDT was found to control the spread of the carriers of diseases such as malaria, typhus, scabies, and cholera.  Not only did it control the spread of disease, it also increased the world's food supply by removing common crop pests.  It could easily obliterate populations of insects. 

However, by the 1960s, the adverse effects of DDT on humans and on the environment became apparent.  These effects were documented in biologist Rachel Carson's famous book, Silent Spring.  Research showed that DDT, which was especially dangerous to humans in oil or organic solvent form, could cause a wide range of problems: dizziness, hyperexcitability, nausea, headaches, tremors, seizures, liver tumors, and even death as a result of respiratory failure.  DDT could be very damaging to the environment as well, causing wildlife sterility and death.

After a great deal of heated legal debate, DDT was banned in the United States in 1972.

OSHA on DDT

The DDT molecule