Discovery
DDT was actually synthesiszed back in 1874 but its potential as a synthetic pesticide was discovered in 1939. The man who discovered this was Paul Muller, and he was awarded the nobel prize in phisiology or Medicine or discovering the highly efficient use against pests and insects.
Immediate Usage
The almost immediate usage of DDT was in europe during World War II. During the war there were many issues with vector borne diseases. DDT was used to kill vectors (an insect or other organism that transmits a pathogenic fungus, virus, bacterium) of diseases such as Malaria and Typhus
Post World War II
Post the world war, in 1945, DDT was comercially produced for use as a synthetic insecticide for agricultural venues. The chemical attracted quick popularity because of its reasonable cost, Persistance, effectiveness, and its versatility. Since it just worked so well it became extremely widespread in usage.
WHO and DDT
The WHO had aided and seen DDT help with the erradication of malaria and europe and so launched a campagin to erradicate malaria worldwide. The whole campaign was backed on the usage of DDT and this wasn't very effective. wide spread commercial use of DDT helped insects develop a resistence to the DDT and so when the areas were sprayed in an attempt to be treated, the vectors resisted and most attempts to stop the malaria spread were completely undone because of this built up resistence. Areas that malaria was successfully erradicated required infrastructure to be able to keep down the disease and maintian health. Developing poorer areas saw a return of malaria and sometimes even worse than before return of it.
Decline in usage
By 1959 however the domestic usage of DDT declined a drastic amount (80million pounds to 12 million pounds annually) because of several reasons
1 - Increased insect resistance
2 - Better alternate pesticides
3 - Public concern of adverse affects
4 - Government restrictions (e.x USDA in 1957)
Exposing the truth
For a long while now, scientists had warned against types of insect and pest control that were chemical based because of their effects on the environment but not until the publication of Silent Spring in 1962 did people really pay attention. The book argued that the "uncontrolled and unexamined" usage of pesticide use was harming and killing animals AND humans. Since DDT was the most commonly used and well known type, it came under fire quickly.
Cat's out of the Bag
Now that the informatio nof DDT was out there people challenged the usage of it and some peopel defended it's usage. The final result was the effective ban of the commercial usage of DDT except in some emergencies. This ban occured june 14th, 1972.
Usage for vector erradication has not been banned but limited.
DDT has been OUTLAWED ( except for in emergencies) in several states in luding Massachusetts but a majority of states simply have strict rules, and regulations about the usage of DDT. Some states simply have restriced use of DDT catagory materials but no specific mention of DDT is in the laws.