these particles are so small they are hard for the lungs to expell. this is the same thing that asbestos causes. it doesnt matter what the foreign subtance is, its the reaction of the body to a foreign substance in the lungs which sets up the problem. that and too little Iodine which is a great expectorant and detoxifier.
"Lack of Iodine in the body is a promoter of cancer." the Iodine project