The rule finalized and published by the Mine Health and Safety Administration in April is the first of its kind to limit silica dust exposure for workers in mines, which is a leading cause of black lung disease among coal miners. Its implementation comes more than 50 years after other industries adopted similar standards to enforce exposure limits based on a wide body of evidence.

In addition to levying limits on exposure and implementing new action levels when a certain amount of silica dust is present in mines, the rule will also require mine operators and companies to offer free medical monitoring for their workers with the hope of detecting black lung and other respiratory diseases earlier.