CDC NIOSH Publications and Products Silica Flour ...
NIOSH also reviewed MSHA silica dust sampling results from the 2 mills and 25 other silica flour mills for 197479. 14 Altogether, 170 inspections were made, representing 1,350 workers. Of 1,142 samples analyzed for respirable silica, 608 (53%) exceeded MSHA''s standard. Only one workplace had no samples in excess of the MSHA standard.