Is there any examples in the history that a chemical is used for a long time, than found to be harmful to human and is finally banned?

asbestos

DDT - an insecticide - is the best known example.

Dioxin
PCB's
Lead (Romans used lead pipes to run water to homes)
Mercury (used in making hats, hence the Mad Hatter from 'Alice')
In the latter two, the usage isn't banned, but no longer used in such capacities.

Asbestos - useful construction material, but very harmful fibres.

Lead

Things like dioxin, PCBs, and DDT are newer examples (last 100 years). However if you look at lead and copper (metal and chemicals), they have/had been used for thousands of years.

thalidomide