User blog comment:Roranoa zoro/Latest Chapter Discussion/@comment-24493980-20141002194747

White Lead : http://en.wikipedia.org/wiki/Asbestos

also Interestingly enough there is a town in Italy called Casale Monferrato " La Citta Bianca " ( The White Town )

And there is an Italian documentary on its history called The White Town

Here's a brief synopsis from Imdb:

"During WWII, on their way to bomb northern Italy English and American pilots could see under them a huge white spot. By that they knew they were flying over Casale Monferrato, The roofs of the houses were, in fact, covered in white by the asbestos dust coming off the Eternit plant opened in Casale Monferrato in 1917. Throughout the plant's production life a massive quantity of asbestos dust was dispersed into the atmosphere. The countryside, communities and water supplies around the plant were contaminated. More than 1,600 people have died in Casale Monferrato for asbestos related pathologies. The victims were not only Eternit workers, but also town inhabitants not related to the factory. "