1. Federal Coal Mine Health and Safety Act of 1969 in Pub. L. No. 91‐173 S. 2917.1969.http://www.msha.gov/SOLICITOR/COALACT/69act.htm Accessed August 6 2018.
2. Federal Mine Safety and Health Act of 1977 in Pub. L. No. 91‐173 as amended by Pub. L. 95‐164.1977.https://arlweb.msha.gov/REGS/ACT/ACTTC.HTM Accessed November 26 2018.
3. Continued Increase in Prevalence of Coal Workers’ Pneumoconiosis in the United States, 1970–2017
4. MSHA fact sheet.https://arlweb.msha.gov/endblacklung/docs/factsheet.pdf Accessed September 24 2018.
5. National Institute for Occupational Safety and Health (NIOSH). Criteria for a recommended standard: Occupational exposure to respirable coal mine dust DHHS (NIOSH) Pub. No. 95–106. Cincinnati OH: NIOSH 1995.https://www.cdc.gov/niosh/docs/95‐106/pdfs/95‐106.pdf Accessed April 4 2018.