Finding of Emergency Section 5204 , Occupational Exposures to Respirable Crystalline Silica Business Meeting : December 14 , 2023 Page 5 of 36
3 ) Silicosis primarily affects workers .
Workers in the occupations of mining , quarrying and sandblasting have long been recognized to be at risk of exposure to RCS , and of developing — and dying from — silicosis . 10 For example , a four-year follow-up study of 83 former sandblasters , from an initial worker population of 145 , found that about 6 % had died in the intervening four-year period , at an average age of 24 years . Among the 74 former sandblasters still alive and available for reexamination , the prevalence of silicosis had increased from 55 % to 96 %, despite short-term exposures and a disease latency of only four years . 11
Investigators in the United States ( U . S .) and worldwide have identified RCS exposures and silicosis among workers in the artificial stone industry more recently . To date , the disease profile among these workers has proved to be particularly aggressive .
4 ) Artificial stone contains more than 93 % crystalline silica .
Artificial stone contains more than 93 % crystalline silica , in combination with adhesives and pigments ( Figure 1 ). 12 In contrast , other stone materials used in countertops contain between 10 % and 45 % crystalline silica ( granite ) or little to no silica ( marble ). An analysis of silica dust generated from cutting and grinding artificial stone found that about 54 % of the dust particles were in the respirable range of ≤10 µ m . 13
Figure 1 . Silica Content of Artificial Stone Compared to Natural Stone .
Stone Artificial stone
≥93
Quartzite |
95 |
Quartzitic sandstone |
90 |
Sandstone |
60 |
Granite |
10 to 45 |
Slate Soapstone
Varies Varies
Average % Silica
10
NIOSH ( 2002 ). Health effects . op . cit . https :// www . cdc . gov / niosh / docs / 2002-129 / default . html .
11
Akgun M , et al . Silicosis Appears Inevitable . op . cit . https :// pubmed . ncbi . nlm . nih . gov / 25654743 / .
12
Occupational Safety and Health Administration ( OHSA ) and National Institute for Occupational Safety and Health ( NIOSH ) ( 2015 ). Hazard Alert : Worker Exposure to Silica during Countertop Manufacturing , Finishing and Installation . Publication number 2015-106 . https :// www . osha . gov / sites / default / files / publications / OSHA3768 . pdf . Accessed May 2 , 2023 .
13
Carrieri M , et al ( 2020 ). Characterization of Silica Exposure . op . cit . https :// www . ncbi . nlm . nih . gov / pmc / articles / PMC7345731 /.