EHOH Presentation

Hazards of Silica Dust Exposure

for Fracking Workers

Group 13: Marisol Chavez, Nicholas Ellinwood, Andres Guerrero, Amy

Klapheke, Mikaela Miller

EHOH 6614

April 7, 2014

Outline

● What is fracking?

● Who are the fracking workers?

● How are they exposed to silica dust?

● What are the health consequences of this exposure?

● Findings from NIOSH Article

● What is being done to address this issue?

image source: http://en.wikipedia.org/wiki/File:Hydraulic_Fracturing-Related_Activities.jpg

Fracking Workers

• 2010: 435,000 workers in the

US oil and gas industry,

about half employed by well

servicing companies,

including those that perform

fracking.1

• Non-union crews, primarily

young men.

• Often housed in trailers by

the drilling companies.http://www.cnn.com/2013/04/25/opinion/radford-ruffalo-natural-gas-fracking/

Fracking Workers

• Fracking operations are exempt from most clean air and water laws

• Most health and safety concerns have been focused on the environment–

especially groundwater contamination

• Due to lack of attention on workers’ health NIOSH initiated the Field Effort

to Assess Chemical Exposures in Oil and Gas Extraction Workers:

o Goal: develop partnerships with oil and gas industry to identify and

control workplace exposures

• Finding that workers are at risk of serious health issues due to exposures

at fracking sites– crystalline silica exposure

Crystalline Silica Exposure

● Each stage of fracking involves

hundreds of thousands of pounds of

crystalline silica, in the form of “frac

sand.”2

● Sand is used as a proppant to hold

open the fissures created by

hydraulic fracturing and allow the gas

to flow out of the shale into the well.2

● National Institute for Occupational

Safety and Health (NIOSH), “1.7

million US workers exposed to

respirable crystalline silica every

year, although the true extent of the

problem is likely greater” 3http://www.entrepreneur.com/article/223219

Crystalline Silica Exposure

● The NIOSH recommended exposure limit (REL) is 0.05 milligrams

of respirable silica per cubic meter of air (mg/m3) as a time-

weighted average (TWA) for up to a 10hr day to reduce silica

related diseases.

● In 2012, OSHA issued a hazard alert for silica after NIOSH found

excessive silica exposure at 11 sites in 5 states3

● “Inhalation of respirable crystalline silica can cause silicosis, lung

cancer, autoimmune disorders, kidney disease, and an increased

risk of tuberculosis”4

Crystalline Silica Health Effects

● Silicosis: irreversible, sometimes fatal, lung disease that

is only caused by inhaling respirable silica dust.3

● Mortality statistics undercount cases, death certificates

show an average of 162 deaths annually from 2000-

2005.1

● Develops over long periods of exposure, progresses

gradually

● Acute silicosis: rapidly fatal cases, have been

documented in several working groups

● Lung cancer, pulmonary tuberculosis, other respiratory

diseases

● Autoimmune disorders Slice of Lung Affected by Silicosishttp://en.wikipedia.org/wiki/Silicosis

Occupational Exposures to Respirable Crystalline

Silica During Hydraulic Fracturing Article4

● August 2010- September 2011, NIOSH collected 111 personal breathing samples at

11 sites in 5 states to evaluate worker exposures to respirable crystalline silica

during hydraulic fracking.

● Workers from 15 different job titles volunteered to participate for 3 consecutive

days.

● At each 11 sites, full-shift samples exceeded OSHA REL or the ACGIH TLV by 10

or more times.

○ 93 of 111 (83.8%) of the samples exceeded the TLV.

○ 76 (68.5%) exceeded the REL.

○ 57 (51.4%) exceeded a calculated PEL for respirable dust containing silica.


Silica During Hydraulic Fracturing Article4

1. Dust ejected from thief hatches (access ports) on top of the sand movers during refilling

operations while the machines are running (hot loading).

2. Dust ejected and pulsed through open side fill ports on the sand movers during refilling

operations

3. Dust generated by on-site vehicle traffic.

4. Dust released from the transfer belt under the sand movers.

5. Dust created as sand drops into, or is agitated in, the blender hopper and on transfer belts.

6. Dust released from operations of transfer belts between the sand mover and the blender;

7. Dust released from the top of the end of the sand transfer belt (dragon’s tail) on sand movers.


Silica During Hydraulic Fracturing Article

• Workers typically wore elastomeric half mask, air-purifying (or

filtering-facepiece style) respirators.

• The half-masks may not be sufficiently protective.

Addressing Silica Exposure

What can be done in the workplace?

Hierarchy of controls

What can agencies do?

OSHA and NIOSH

Hierarchy of Controls

Elimination of silica dust

● Proppants cannot be eliminated from

the fracking process

Elimination of hydraulic fracturing

● Fracking itself can not be eliminated,

otherwise the energy demands of the

USA will depend on expensive imports

○ 43% of total U.S. oil production

and 67% of natural gas

production comes from fracking5

● Alternative energy sources may

supplement energy supply, but will not

completely replace oil and gas anytime

soon


Substitution

• Alternative materials as proppants

• Sintered bauxite, ceramics

• Respirable particulate matter still a

concern

● May have similarly harmful

effects


Engineering Controls1

• Enclose points where dust is released

• Use enclosed cabs or booths with

HEPA filters and climate controls

• Use local exhaust ventilation

• Replace transfer belts with screw

augers on sand movers in new designs

or retrofits

http://www.lubing.com/auger-conveyor.html


Administrative Controls1

• Mandate the capping of unused fill

ports (e.g., cam lock caps) on sand

movers.

• Reduce the drop height between the

sand transfer belt and T-belts and

blender hoppers.

• Limit the number of workers, and the

time workers must spend in areas and

consider ways to perform dusty

operations remotely

• Apply fresh water to roads and around

the well site to reduce the dust.


Personal Protective Equipment

• Masks for all workers that meet

maximum exposure levels

o Simple measure

o Only required when exposure

exceeds the relatively high

OSHA standard

o NIOSH study found many

exposures exceeded levels

approved for masks used


Education

• Improve training and awareness in

work force

o Various companies, short-term

contracts, and a transient work

force make education measures

not feasible

o Least effective measure in

hierarchy


Various controls and guidelines exist6

http://www.ussilica.com/uploads/files/product-group-msds/msds/silica-msds-english.pdf


No harmonized classification of crystalline silica7

TSCA No.: Appears on the EPA TSCA inventory

RCRA: Not classified as a hazardous waste under the Resource Conservation and Recovery Act.

CERCLA: Not classified as a hazardous substance under Comprehensive Environmental Response Compensation

and Liability Act

Emergency Planning and Community Right to Know Act: Not an extremely hazardous substance or a toxic chemical

Clean Air Act: Does not contain any Class I or Class II ozone depleting substances.

NTP: Classified as a known human carcinogen.

OSHA Carcinogen: Crystalline silica is not listed.

California Proposition 65: Classified as a substance known to the state of California to be a carcinogen.

California Inhalation Reference Exposure Limit (REL): The California chronic REL for respirable crystalline silica is 3

ug/m3

Massachusetts Toxic Use Reduction Act: Considered toxic

Pennsylvania Worker and Community Right to Know Act: Considered hazardous


• OSHA has proposed a new regulation

• Current PEL’s for crystalline silica

exposure were adopted in 1971 and

based on research from the 1960s

• Proposed regulation would provide

consistent levels of protection for

workers in all sectors covered by the

rule

• Exposures would be limited to 50

µg/m3 of respirable crystalline silica

averaged over an 8 hour day

http://blogs.cdc.gov/niosh-science-blog/2012/05/23/silica-

fracking/

Conclusion

● There are many hazards

for fracking workers

● Crystalline silica

exposure needs to be

controlled

● We need to work

towards a standard

exposure limit

● More research!

http://www.npr.org/blogs/health/2013/03/29/175042708/Sand-From-Fracking-Operations-

Poses-Silicosis-Risk

Resources

1. Esswein, J.E., Kiefer, M., Snawder, J., & Breitenstein, M. (2012). Worker Exposure to Crystalline Silica During

Hydraulic Fracturing. NIOSH Science Blog. Retreived from http://blogs.cdc.gov/niosh-science-

blog/2012/05/23/silica-fracking/.

2. OSHA. (2012). Hazard Alert: Worker Exposure to Crystalline Silica During Hydraulic Fracturing. Retrieved from

https://www.osha.gov/dts/hazardalerts/hydraulic_frac_hazard_alert.html1

3. Grossman, E. (2013). Silica exposure in fracking: Over 60 percent of workers may be excessively exposed. The

Pump Handle. 2

4. Esswein, J. E., Breitenstein, M., Snawder, J., Kiefer, M., and Sieber, K. W. (2013). Occupational Exposures to

Respirable Crystalline Silica During Hydraulic Fracturing. Journal of Occupational and Environmental Hygiene. 10:

347-356.3

5. US Dept. of Energy. (2013). How is Shale Gas Produced? Retrieved from

http://energy.gov/sites/prod/files/2013/04/f0/how_is_shale_gas_produced.pdf.4

6. Proppant Specialists, LLC. (2008). Silica Sand [Material Safety and Data Sheet]. Retrieved from

http://oilandgas.ohiodnr.gov/portals/oilgas/_MSDS/fractech/Silica_Sand.pdf.5

7. U.S. Silica Company. (2012). Silica Sand and Ground Sand [Material Safety and Data Sheet]. Retrieved from

http://www.ussilica.com/uploads/files/product-group-msds/msds/silica-msds-english.pdf.6

https://www.osha.gov/dts/hazardalerts/hydraulic_frac_hazard_alert.html1

http://oilandgas.ohiodnr.gov/portals/oilgas/_MSDS/fractech/Silica_Sand.pdf.5

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