Why did the United States ban the use of DDT?
DDT is a pesticide.
DDT is a very unfortunate pesticide we used mainly in the mid to late 20th century.
It was developed in the 1940s & was the first of new synthetic pesticides, it was used to great effect to combat insect spread diseases such as Malaria & Typhus.
But during inspections of the DDT pesticide during the 1950s & 1960s by the U.S. Department of Agriculture, an agency in charge of regulating pesticides before the U.S. Environmental Protection Agency in 1970, found evidence of the negative effects of DDT's benefits, it's impact on the environment & the toxicity of it, slowly prohibiting it's uses.
In 1972, not long after the forming of the U.S. Environmental Protection Agency, a cancellation order of the pesticide was made on it's effects on Wildlife & the possible risk towards humans.
An example of the effects that were seen on Wildlife were that of the collapse of Peregrine Falcon numbers;
The birds the Falcons hunted ate insects killed by DDT, the insect eating birds would gradually get a build up of DDT inside themselves which would be passed onto the Falcons once they were killed & eaten, this concentrated DDT into the Falcons,
Falcons had a large amount of DDT build up in them & one of the negative effects it had on them was on their egg's, the shells of the eggs were thinner & a lot less stronger than they should be, they couldn't support the growing offspring.
You can work out the rest from there.
Hope this helps.