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Respirable Crystalline Silica (RCS) Project Experience

Industrial Hygiene Experience | Occupational Health Experience

Industrial Hygiene RCS Project Experience​

Exposure to RCS has been associated with many health conditions including silicosis (a fibrosis of the lung), lung cancer, chronic obstructive pulmonary disease (COPD), and kidney and immune system disease. The Occupational Safety and Health Administration (OSHA) estimates that approximately 2.2 million workers in the United States are exposed to RCS in their workplaces. The various work environments where employees are exposed to RCS include mining (including industrial minerals and aggregate mining), construction, concrete and brick manufacturing, foundry work, hydraulic fracturing (fracking) and sandblasting.


SOMA has performed extensive sampling and has in-depth field experience in evaluating exposures or the potential for exposures to airborne chemical hazards including particulates, gases, fumes and vapor, for both current conditions as well as historical exposure retrospectively. Specifically, SOMA staff have collected over 20,000 RCS samples. With our state-of-the art sampling equipment, we have been able to respond promptly to our clients needs and complete the on-site sampling in a timely manner.


Our staff has a combined experience of over 75 years of comprehensive, hands-on knowledge working with a number companies to minimize employee exposure to RCS. The client size ranges from small single site employers to large-scale clients with multiple sites distributed nationwide. We have collected RCS samples for the following:

  • Mining Industry - Surface Aggregate/Industrial Minerals Mining/Extraction Sites, Underground Mines

  • Utilities Industry

  • Construction Sites

  • Manufacturing Facilities - Industrial Minerals, Cosmetics, Chemical Plants

  • Ready-Mix Concrete Plants

  • Cement Plants

  • Asphalt Plants

  • Road Paving Projects

  • Railroad Operations

  • Commercial Properties

One of our large-scale clients include an aggregates leader with over 300 locations across the United States, Canada, and the Bahamas. Their products include a variety of aggregates, ready-mix concrete, asphalt and cement facilities. SOMA has provided ongoing consulting services (industrial hygiene and occupational health) for this organization for the past 19 years, including a comprehensive evaluation of exposures to RCS. We have assisted with ensuring regulatory compliance (MSHA/OSHA) specifically related to RCS. The project approach to assess exposures to RCS includes:

  • Collecting air samples (personal and/or area) on-site to be analyzed for RCS

  • Recording work conditions and existing control measures that may affect the sampling results

  • Delivering the collected samples to an accredited laboratory for RCS analysis;

  • Interpreting the lab results

  • Presenting the findings to the client. This has included regular re-evaluation of sampling strategies and prioritization of efforts.  The sampling strategy has been refined to identify similar exposure groups (SEGs) and focus on the most at-risk SEGs

  • Recommending control actions depending on whether exposures are at or above regulated or permissible exposure levels

  • Developing and maintaining a robust database and generating exposure models based on the existing sampling results to predict the employee exposures for others performing similar tasks. The database not only allows tracking of specific SEGs over time, but also records and documents implementation of control measures pursuant to exposure concerns. The exposure modeling experience also allowed us to identify to the client as to how to best focus their resources to reduce or eliminate RCS exposures

The comprehensive approach of evaluating the on-site RCS exposures, identifying areas with the potential to exceed regulatory standards, providing recommendations for appropriate control measures combined with tracking the effectiveness of the control measures implemented, resulted in a continuing downward trend of RCS exposures for the client.


Based on the exposure evaluation as well as other client historic data, we were able to prepare Safety Data Sheets (SDSs) formerly Material Safety Data Sheets (MSDSs) for products containing crystalline silica. In addition to RCS exposure assessment, SOMA also developed Respiratory Protection Programs its clients and has provided recommendations on the appropriate selection of respirators to reduce employee exposures to RCS.  

Occupational Health RCS Project Experience


SOMA has extensive experience in providing RCS-related occupational health services and monitoring for the wide and expanding range of RCS-related industries, extending over two decades.  This experience includes continuous medical monitoring-surveillance activities of large workforces, totaling well over 10,000 employees collectively, and monitoring and management of ILO-positive active employees.  SOMA’s collective occupational physician expert experience in RCS exceeds 50 years. SOMA also serves as external medical director for RCS medical surveillance service providers, extending across multiple industries and inclusive of many thousands of employees.  SOMA works closely on a continuous basis with all of these industrial clients in the management of workforce testing and monitoring, ensuring regulatory compliance and adaptation to new requirements as they occur. SOMA has extensive experience in the deployment of efficient RCS program ancillary services including x-ray ILO report acquisition, B-reader selection and management, consensus ILO reading management, alternative cause evaluation, and outcome notification-communication requirements.  SOMA provides long-term record and x-ray image management services, as well as workforce surveillance data maintenance and analyses, and trend evaluations across the wide range of RCS-related industries.


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IH Experience
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