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Silicosis: Number of silicosis cases by large opacity category on the International Labour Organization (ILO) report—Michigan and New Jersey, 1993–2011

ILO ResultsMichiganNew JerseyTotal
PMF1 123   19.1   29   22.0 152   19.6
Category A   65   10.1   12     9.1   77     9.9
Category B   51     7.9    9     6.8   60     7.7
Category C    7     1.1    8     6.1   15     1.9
No PMF 522   80.9 103   78.0 625   80.4
TOTAL 645 100.0 132 100.0 777 100.0

1 Large opacities are defined as any opacity greater than one centimeter. They are classified into three categories: A, B, and C. Categories A, B, and C represent progressive massive fibrosis (PMF).


The total number of cases by state and overall represent those cases with an available ILO report with no missing information.

Thirty of the 903 confirmed silicosis cases did not have an available report and ninety-six cases from New Jersey had missing information on the available ILO report.

Percentages are based on available ILO reports with large opacity category information and may not sum up to 100% due to rounding.

See Appendix for more information.


Sentinel surveillance data as of January 2015, reported by K Rosenman, MJ Reilly, and M Yoder (Michigan); M Lumia and K Worthington (New Jersey).


NIOSH 2015. Work-Related Lung Disease Surveillance System (eWoRLD). 2015-850 U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Respiratory Health Division, Morgantown, WV. Available at: <> January 23, 2019.

Reference Number: 2015-850

Date Posted: July 2015

Archived Version