Workers at surface mining operations are often exposed to high levels of silica and other types respirable dust. In an effort to lower these respirable dust exposures, the National Institute for Occupational Safety and Health (NIOSH) has been conducting research to address this problem in a practical and economically viable manner. Lowering the dust exposure of equipment operators in enclosed cabs has been a major focus of research efforts over the past several years. Many types of operations utilize enclosed cabs to protect equipment operators from dust exposure. Normally when the equipment is new, the cabs are fairly airtight. These tightly sealed cabs, combined with good filtration systems, generally provide the operator with good dust protection. However, at most operations, the equipment is older. As aging occurs, many components of the enclosure deteriorate, the structural integrity of the cab diminishes and the effectiveness of the air filtration system fails. NIOSH has been successfully researching cost-effective methods to improve both filtration effectiveness and cab integrity of these older cabs in order to provide a healthier work environment for equipment operators.