U.S. Department of Labor Occupational Safety and Health Administration

What compliance methods must employers use to control exposures?
You must control exposures to or below the PELs using engineering controls and work practices to the extent feasible.

Where feasible engineering controls and work practices do not ensure worker protection at the exposure limits, you must reduce employee exposures to the lowest levels achievable and then supplement them with respiratory protection to meet the PELs.

In construction and shipyards, each work classification has specific control method requirements.

In general industry, specific controls are prescribed for brake and clutch repair work. For example, you must prohibit certain practices, such as the use of compressed air, to remove asbestos.