DDT is banned by the US EPA because the associated risks so heavily outweigh any benefits. It causes environmental damage because it does not dissipate. Once ingested, it can accumulate and remain in fatty tissues and can spread into the atmosphere. It has been linked to cancer, and exposure has been linked to reproductive defects in humans and animals. It should only be used, after careful consideration in countries where malaria is a greater threat to human life.
DDT levels measured in the wild even after extensive DDT use as a pesticide have never come close to the levels required to kill organisms as demonstrated by controlled lab experiments.
The supposed link to thinning egg shells was only ever a loose statistical association based on a few types of birds whose shells were already thinning in some cases.
DDT is probably one of the safest pesticides ever discovered, when it comes to poisoning some animals but not others it doesn't get any better than this.
It kills not only mosquitoes, but also animals. DDT has a role to play; but DDT is not a panacea, DDT is much more toxic to non-target species than other pesticides, DDT's effectiveness fades rapidly with use, and reliance on DDT as a panacea stunts progress in other areas of the fight against malaria.
DDT is not a safe pesticide to use. Many animals, including innocent ones, end up dying because of this pesticide, especially the fish. What about ourselves? The reason why it's considered "safe" is because DDT can't really make it through our skin. But, once in, it could affect us, from tremors, twitches, and headaches, to certain death. So, using DDT could cause
DDT is an extremely harmful pesticide that causes problems for many different organisms and is terrible for the environment. We now have much better technology for farming, and can genetically modify food plants to make them heartier and more disease and pest resistant without creating any environmental risk from toxins like DDT. We should use these newer, safer technologies instead.