ACMA recently called on industry members to contact OSHA regarding the proposed silica standard that will increase costs for many composites companies without providing workers any health benefits. Information about the rule and guidance for writing to OSHA are available at

At the heart of the issue is OSHA’s failure in its preliminary economic analysis (PEA) to consider the use of silica containing materials by composites manufacturers, except for one highly atypical manufacturer of “engineered stone.” As a result, the proposed control requirements may not provide sufficient protection for composites industry workers nor be technically or economically feasible.

Many composite raw materials and molded composite products contain crystalline silica. According to OSHA, prolonged inhalation to respirable crystalline silica at high concentrations may lead to the development of disabling and sometimes fatal lung diseases, including silicosis and lung cancer.

Sand and quartz are comprised primarily of crystalline silica. Calcium carbonate, gypsum, dolomite, mica and other materials used in the production of cast polymer, engineered stone, tub/showers, molding compound and many other composite products contain crystalline silica at lower levels.

 OSHA’s Proposed Regulation

Under the OSHA proposal, employers would be required to conduct an initial assessment of occupational exposure to silica. If 8-hour average exposures exceeded an action level of 25 µg/m3 (micrograms per cubic meter of air), the employer would be required to implement a periodic monitoring program.

For workplaces where 8-hour average exposures exceed a revised permissible exposure limit (PEL) of 50 µg/m3, employers would be required to install engineering controls and adopt work practices to reduce exposures to the extent possible. Job rotation would not be permissible as a technique to reduce silica exposures.

If exposures still exceeded the PEL after installation of engineering controls and adoption of work practices, personal protective equipment (PPE) could be used to meet the PEL. Employers must establish procedures to prevent unauthorized employees from entering areas where they might be exposed to silica in excess of the PEL. Regular medical monitoring of employees would be required.

ACMA is working with OSHA to assess composites industry workplace exposure and control options. Exposure limits and other OSHA information about crystalline silica can be found at For updates and analysis, turn to CM Online at and click the “Government Affairs” tab.