MSHA final rule lowers limit for miner exposure to silica

Arlington, VA — The Mine Safety and Health Administration has issued a long-anticipated final rule that lowers miners’ permissible exposure limit to respirable crystalline silica.

Set to be published in the April 18 Federal Register, the rule lowers the PEL for respirable crystalline silica to 50 micrograms per cubic meter of air – half the current limit – over an 8-hour time-weighted average. The rule also increases silica sampling and enforcement at metal and nonmetal mines and requires mine operators to provide periodic health exams at no cost to miners.

Workers can inhale silica dust during mining and other operations, including cutting, sawing, drilling or crushing materials such as rock and stone. Crystalline silica can damage lung tissue and lead to black lung disease, chronic obstructive pulmonary disease or silicosis, which NIOSH defines as an “irreversible but preventable lung disease.”

The rulemaking first appeared on the Department of Labor’s regulatory agenda in 1998. OSHA estimates that about 2.3 million workers are exposed to silica dust each year. The new PEL matches the PEL OSHA established in 2016.

“It is unconscionable that our nation’s miners have worked without adequate protection from silica dust despite it being a known health hazard for decades,” acting Labor Secretary Julie Su said in an April 16 press release. “Today, the Department of Labor has taken an important action to finally reduce miners’ exposure to toxic silica dust and protect them from suffering from preventable diseases.”

The final rule is set to go into effect in June. However, certain provisions won’t become effective until either June 2025 or June 2026.

Multiple worker groups applaud the rulemaking, which MSHA estimates will save nearly 1,100 lives and prevent more than 3,700 cases of silica-related illness.

To Cecil Roberts, president of United Mine Workers of America, the rule protects miners both in the short term and throughout their lives.

“Young miners in their 30s and 40s are getting lung diseases that are being exacerbated by silica dust,” Roberts said in a release. “What was thought to be a disease of the past is coming back with a vengeance because miners are cutting more rock than ever before.”

In a separate release, AFL-CIO President Liz Shuler calls the rule “a definitive step toward safeguarding the health and well-being of our nation’s miners.”