Silica is the new asbestos, according to reports.
It is understood that US Silica has been hit with 22,000 claims up from just over 3,000 last year.
Silica, which is used in building materials, creates silica dust which causes silicosis, a serious lung condition.
US health monitors say the number of cases of silicosis has fallen in recent years to a few hundred.
But class action lawyers say the surge in claims is the result of early diagnosis of the disease.
