Silica Larry Joswiak, MPH March 31, 2010

1. Silica Larry Joswiak, MPH March 31, 2010

2. It’s not just dust…It’s silica Silica NEP (National Emphasis Program) January 24, 2008 Silica LEP (Local Emphasis Program) October 1, 2009 Targets specific General Industry SIC Codes Silica 1926.55 – Mineral Dusts

3. What is silica? • Mineral – crystalline or amorphous forms • Crystalline most hazardous • Crystalline- 3 forms • Quartz, cristobalite, tridymite • Quartz – most common Major component of soils and readily found in rock Granite ~30% quartz Shale ~ 20% quartz Beach sand – nearly pure quartz

4. Sand/abrasive blasting Tuckpointing Jack hammering concrete Brick/block cutting Concrete cutting & drilling Demolition Stone cutting Foundry work Tunneling Rock drilling Quarrying Silica Exposure Activities

5. What is silicosis? • A disabling and often fatal lung disease caused by breathing very small “respirable” particles of crystalline silica • >14,000 deaths since 1968 • >200 deaths each year in the U. S.

7. Silicosis • Chronic/Classic • Occurs after 15 – 20 years of moderate to low exposure • Accelerated • Occurs after 5 – 10 years of high exposures • Acute • Occurs after a few months or as long as 2 years to extremely high concentrations

8. Other Health Effects of Silica Exposure • Lung cancer • IARC Group 1: Carcinogenic to Humans • Tuberculosis • Chronic Obstructive Pulmonary Disorder • Bronchitis, Emphysema • Immunologic Disorders & Autoimmune Disease • Renal Disease

9. Diseased and healthy lung • Compare these sections cut from a diseased lung with large cavities (left) and a pink, healthy lung (right). The diseased lung shows a case of miner’s phthisis (also known as silicosis) which has led to tuberculosis. Quartz dust is inhaled by miners, and trapped in the lungs causes silicosis making the victim more susceptible to diseases such as tuberculosis and pneumonia.

10. Current Respirable Silica Quartz Exposure Limits OSHA (PEL) Construction OSHA (PEL) General Industry ACGIH (TLV) 250 mppcf 10 mg/m3 Quartz: 0.025 mg/m3 Cristobalite: 0.025 mg/m3 % silica + 5 % silica + 2

11. AIR SAMPLING EQUIPMENT Personal Air Pump with Cyclone

12. PERSONAL SAMPLING

13. a 8-hour Time Weighted Average d mg/m3 – milligrams per cubic meter of air b OSHA Permissible Exposure Limit e mppcf – million particles per cubic foot of air c Employee exposure for time sampled f TLV – American Conference of Governmental Industrial Hygienist’ Threshold Limit Values

14. 6 % silica 2.27 mg/M3 PEL 16.3 mg/M3 (68 min) 2.31 mg/M3 8 hr TWA 8 hour severity 102% of PEL EXCEEDED PEL Gas saw dry cuts hole in concrete manhole 718 % of PEL for 68 minute sample time Concrete Cutting (Dry) Example

15. 30% Crystalline Silica Quartz

18. 10% Crystalline Silica Quartz

23. 8 % Crystalline Silica Quartz 10% Crystalline Silica Quartz

25. Dry operations: High likelihood of silica dust overexposure Wet operations: Low potential for silica dust overexposure Exposures may be multiplied by factors such as interior workplace and corner location. Silica Conclusions

26. Silica Conclusions • Written Hazard Communication Program • Employee training on silica • Engineering Controls • Use of water during cutting • Local exhaust ventilation • Respiratory Protection • NIOSH approved • Air Monitoring • Required or voluntary use • Eye Protection