If you want to learn about our products , please call or write mail consultation.
3concentration of silica in excess of the pel of 50 gm 3 calculated as an 8-hour twa. 29 c.f.r. 1910.1053c. employers must assess the exposure of each employee who is or may reasonably be expected to be exposed to respirable crystalline silica at or above the al using either a performance option or a scheduled monitoring..