Center for Asbestos Safety

Mine Safety and Health Administration Meetings on Asbestos Exposure Levels

The Mine Safety and Health Administration had conducted a series of public meetings in 2002 to discuss the creation of new rules regarding how workers are exposed to the toxic mineral asbestos. The meetings covered the potential recommendation to the Department of Labor to lower the Permissible Exposure Limit (PEL) for asbestos workers as well as examining the problem of workers who may unknowingly carry asbestos home on their clothes, inadvertently exposing their families to the dangerous material.

The meetings also examined the costs of changing the department’s set of analysis tools from Phase Contrast Microscopy (PCM) to Transmission Electron Microscopy (TEM). MSHA was employing PCM at the time, which could magnify fibers by a factor of more than four hundred. The TEM microscopes can magnify fibers by a factor of twenty thousand or more, allowing for a better analysis of the concentration of fibers within an air sample.

Control and Prevention of Asbestos Exposure from Construction in Naturally Occurring Asbestos

During the construction of an underground parking garage in Fairfax County, Virginia, in 1987, workers encountered a sizable vein of tremolite asbestos ore. When the work crews disturbed the ore vein, the asbestos fibers became loose and airborne, falling as white dust and causing skin irritation and itching among the crews. Other construction and land development projects have encountered similar problems when workers unwittingly expose natural asbestos ore deposits.

Asbestos exposure is also known to cause severe respiratory problems when workers breathe in the dust without the protection of special masks or particle filters. One of the most frequently occurring health problems that workers exposed to asbestos encounter is pleural mesothelioma, an aggressive and untreatable form of cancer that strikes the protective fluid lining of the lungs.

Officials with the Fairfax County Health investigated the incident as well as other construction projects in the area that encountered natural asbestos deposits. After consulting with several experts in soil science and mineralogy, the department made a number of recommendations to crews working around asbestos, including the use of protective gear, posting warning signs around any area that may be contaminated, and wetting down any dust piles that may contain asbestos fibers.

Center for Asbestos
Safety in the Workplace