Engineering Controls for Crystalline Silica Exposures During Concrete Grinding

Abstract No:


Abstract Type:

Professional Poster 


E Reed1


1Liberty Mutual Insurance Company, Englewood, CO


Edgar Reed  
Liberty Mutual Insurance Company


This study investigated silica exposures and control methods used in concrete grinding and related activities to determine the efficacy of these methods. Task based measurements subsequent to engineering control interventions were compared to values obtained prior to the implementation of these engineering controls. T

Situation / Problem:

Millions of workers are exposed to crystalline silica each year in construction, mining and general industry occupations. Due to the requirements of 29 CFR §1910.1053 Respirable Crystalline Silica, employers are motivated to identify and implement effective control strategies to reduce exposures to this agent. Concrete grinding and related activities can create airborne crystalline silica exposures at levels significantly above published occupational exposure limits.


Pre- and post- control implementation exposure assessments were completed for representative concrete hand grinding and related tasks using NIOSH method 7500. Pre- and post- intervention measurements of the same task were compared to investigate the efficacy of the engineering control interventions (e.g. local exhaust ventilation of hand tools). By determining the effect of the control strategy on the actual exposure due to the specific task, we can compare the results to OSHA requirements and NIOSH recommendations. The control costs were provided by the employer. The cost effectiveness of the implementation of each control strategy was assessed using the OSHA Safety Pays profitability estimator program.

Results / Conclusions:

This study's results include: 1) descriptive statistics of the exposures to respirable crystalline silica; 2) the type and efficacy of the control strategy used; 3) A comparison of the exposure data to governmental and professional exposure standards; 4) an efficacy ranking of the strategies for specific tasks; 5) the cost and cost effectiveness of control interventions; and 6) best practices for typical tasks.

Primary Topic:

Value Strategy, ROI, & Budgets

Secondary Topics:


Acknowledgements and References

List any additional people who worked on the project or provided guidance and support along with details on the role they played in the research. (Please include first name, last name, organization, city, state and country).

Maura Sheehan, Sc.D., CIH, FAIHA, Professor Emeritus, West Chester University of Pennsylvania,
Downingtown, PA USA.

1. National Institute for Occupational Safety and Health (NIOSH). Workplace Safety and Health Topics: Silica. Accessed 9/5/2017 from
2. National Institute for Occupational Safety and Health (NIOSH). (2001). In-depth survey report of four sites: exposure to silica from hand tools in construction chipping, grinding and hand demolition at Frank Messer and Sons Construction Company Lexington and Newport KY; Columbus and Springfield OH. NIOSH report No.EPHB 247-15. Accessed 9/5/2017 from
3. Occupational Safety and Health Administration (OSHA). Estimated Costs of Occupational Injuries and Illnesses and Estimated Impact on a Company's Profitability Worksheet. Accessed 9/5/2017 from

Learning Levels

What learning level(s) is the presentation content geared towards?

Experienced - has a thorough understanding of the content area and work experience including application and evaluation of the content/concepts in a variety of contexts; can vary performance based on unique situations.