Mine & Safety Hazard Approved Lagging (MSHA) should be used in all underground coal mining applications and any application where fire safety is imperative. CCI's MSHA lagging compound has been approved by the United States Federal Government to apply on all pulleys in mining applications where fire safety is required. The MSHA compound is clearly labeled on each pulley and stamped with our government ID in several places on each pulley. Minimum required thickness for MSHA lagging is 1/2".