MSHA to Study Health Effects of Respirable Coal Mine Dust Standards

Published July 11, 2018

MSHA is requesting information from stakeholders to assist the agency in developing the framework for a retrospective study to assess the health effects of its final rule “Lowering Miners' Exposure to Respirable Coal Mine Dust, Including Continuous Personal Dust Monitors,” which went into effect on Aug. 1, 2014, and included a two-year phase-in period. The rule is intended to lower coal miners’ exposures to respirable coal mine dust and improve their health. MSHA stated its intent to conduct this retrospective study when the rule was first published in the Federal Register. The agency originally planned to take the lead on the study beginning in February 2017.

“To be clear, MSHA is initiating the study referenced in the preamble to the final rule to determine if the rule is meeting its intended result,” said MSHA Assistant Secretary David G. Zatezalo. “MSHA has no intention of rolling back the protections afforded to coal miners under the final dust rule.”

Since the rule went into effect, MSHA has been analyzing respirable dust samples taken by mine operators using continuous personal dust monitors and by MSHA inspectors using gravimetric samplers. The agency is using this sample data to evaluate the effectiveness of dust controls in mines and whether its rule is resulting in reduced levels of respirable coal dust. According to MSHA’s analysis, more than 99 percent of these samples are in compliance with its respirable coal mine dust standards.

“However, due to the latency between exposure and disease, MSHA likely will not be able to evaluate fully the health effects of the rule for a decade or more,” the agency cautions in its most recent Federal Register notice.

A recent report published by the National Academies of Science, Engineering, and Medicine questions whether the sampling results analyzed by MSHA are representative of the miners with the highest exposures.

MSHA asks stakeholders to submit comments, data, and information to assist the agency with its retrospective study. MSHA also seeks information and data on engineering controls and best practices that lower miners' exposure to respirable coal mine dust. Stakeholders have one year, until July 9, 2019, to respond to the agency’s request for information. More information on submitting feedback is available in the Federal Register.

The 2014 rule lowered the exposure limit in MSHA’s overall dust standard from 2.0 to 1.5 mg/m3 at underground and surface coal mines, and lowered the limit of 1.0 to 0.5 mg/m3 for intake air at underground mines and for miners who show evidence of developing pneumoconiosis. MSHA’s rule also requires mine operators to collect respirable dust samples for the full shift a miner works, rather than stopping measurement after eight hours; requires immediate corrective actions to lower dust concentrations when a single sample shows an excessive concentration of dust; provides expanded medical surveillance requirements for miners; and strengthens requirements for certified persons who perform dust sampling and maintain and calibrate sampling equipment.

View MSHA’s press release on the agency’s website.