INSTITUTE OF OCCUPATIONAL MEDICINE . Edinburgh . UK www.iom-world.org

Occupational health issues associated with fracking

John Cherrie

Summary…

• Workplace regulations• Hazardous substances• Main potential risk from crystalline silica• Silicosis, COPD, renal failure and lung cancer

• Putting these risks in context• What can be done about this problem?• Appropriate health surveillance• Managing other risks to health

COSHH Regulations

• Finding out what the health hazards are• Undertaking a risk assessment• Providing control measures to reduce harm

to health• Making sure they are used • Keeping control measures in working order• Providing information, instruction and

training for employees and others• Undertaking monitoring and health

surveillance

Occupational Hazards

• Diesel engine exhaust• Volatile organic compounds • Hydrogen sulfide (H2S)

• Acid gases (HCl)• Metals (Pb) • Aldehydes• Water and other additives• Respirable crystalline silica

Exposure to crystalline silica

• NIOSH measured exposure levels at 11 fracking sites in 5 states

• NIOSH Recommended Exposure Limit REL = 0.05 mg/m3 as an 8-hour average

• British Workplace Exposure Limit WEL = 0.1 mg/m3

Esswein EJ, Breitenstein M, Snawder J, Kiefer M, Sieber WK (2013) Occupational exposures to respirable crystalline silica during hydraulic fracturing. J Occup Environ Med 10: 347–356.

With permission from Eric J. Esswein, NIOSH

With permission from Eric J. Esswein, NIOSH

Crystalline silica

Esswein EJ, et al (2013) Occupational exposures to respirable crystalline silica during hydraulic fracturing. J Occup Environ Med 10: 347–356.

Respirable crystalline silica in EU

Main hazards from crystalline silica

• Silicosis• Tuberculosis• Chronic obstructive pulmonary disease• Lung cancer• Chronic renal disease• Scleroderma• Rheumatoid arthritis

Risks from USA silica sand workers

Cause of death (SRR)

<0.1 mg/m3.yr

0.1-0.5 mg/m3.yr

0.5-1.28 mg/m3.yr

>1.28 mg/m3.yr

p for trend

Lung cancer (15 yr lag)

1.0 0.78 1.51 1.57 0.07

Silicosis 1.0 1.22 2.91 7.39 <0.00001

Other resp. disease, inc silicosis

1.0 1.63 1.45 2.4 0.02

• Steenland and Sanderson (2001)• 4,626 industrial sand workers• Average employment was 9 years and

estimated average exposure was 0.05 mg/m3

Steenland K, Sanderson W (2001) Lung cancer among industrial sand workers exposed to crystalline silica. Am J Ind Med 153: 695–703.

Risks from UK silica sand workers

• Brown and Rushton (2005)• 2,703 employees / former employees at seven

quarries• Overall geometric mean silica concentration was

0.09 mg/m3

Brown TP, Rushton L (2005) Mortality in the UK industrial silica sand industry: 2. A retrospective cohort study. Occup Environ Med 62: 446–452.

Cause of death (RR)

<0.13 mg/m3.yr

0.13-0.4 mg/m3.yr

0.4-1.0 mg/m3.yr

>1.0 mg/m3.yr

p for trend

Lung cancer (no lag) 1.0 1.14 1.12 0.92 0.80

Non-malignant resp. disease

1.0 1.33 0.98 1.12 0.98

Silica surface properties…

• IARC noted… “carcinogenicity in humans was not detected in all industrial circumstances studied, carcinogenicity may be dependent on inherent characteristics of the crystalline silica…”

• Cancer and silicosis risk most probably arise from inflammation

• Key physicochemical parameters are surface reactivity and particle size (surface area)

Borm PJA, Tran L, Donaldson K (2011) The carcinogenic action of crystalline silica: A review of the evidence supporting secondary inflammation-driven genotoxicity as a principal mechanism. Crit Rev Toxicol 41: 756–770.

Surface treated quartz

Duffin R, Tran CL, Clouter A, Brown D, MacNee W, et al. (2002) The Importance of Surface Area and Specific Reactivity in the Acute Pulmonary Inflammatory Response

to Particles. Ann Occup Hyg 46: 242–245.

Health surveillance

• Where there is a reasonable likelihood of silicosis developing, health surveillance will be necessary.

• Baseline assessment of health status • Clinical examination• Work history information• Chest x-rays • Symptoms questionnaire / lung function• Screening for chronic kidney disease?

Exposure controls

• Prevention through Design• Remote operations • Substitution (ceramic vs. sand) • Mini‐baghouse, screw augur assemblies • Passive enclosures, e.g. stilling curtains • Minimize distance that sand falls • End caps on fill nozzles • Effective respiratory protection

program

Questions?

NIOSH proposed mini-baghouse unit

My slides are available at www.Slideshare.net/JohnCherrie