update on a niosh engineering control for respirable ... to prevent workplace ... production testing...

Update on a NIOSH Engineering Control for Respirable Crystalline Silica at Hydraulic Fracturing Operations

Bradley King, PhD, MPH, CIH NIOSH Western States Office

Acknowledgements • Eric Esswein, MSPH, CIH • Barbara Alexander, PhD, PE • Michael G. Gressel, PhD, PE • Jerry L. Kratzer • H. Amy Feng, MS • Arthur L. Miller, PhD • Emanuele Cauda, PhD • John Snawder, PhD • Michael Breitenstein

December 2-3, 2014

NIOSH thanks our industry partners (esp. their employees) for their leadership, commitment, and vision to OS&H and for their participation in NIOSH Safety & Health Research in Upstream Oil and Gas Extraction.

December 2-3, 2014

Acknowledgements

The findings and conclusions in this presentation have not been formally disseminated by NIOSH and should not be construed to represent any agency determination or policy.

December 2-3, 2014

Disclaimer

• U.S. Department of Health and Human Services

• Centers for Disease Control and Prevention

• A Research Agency • Non-regulatory • “Assure safe and healthful

working conditions for all workers”

• Not OSHA (Dept. of Labor)

• Providing National and World Leadership to Prevent Workplace Illnesses and Injuries

• Locations – Office of the Director: Washington, DC – DART, DSHEFS: Cincinnati, OH – WSO: Denver, CO – HELD: Morgantown, WV – OMSHR: Spokane, WA – OMSHR: Pittsburgh, PA – APO: Anchorage, AK

December 2-3, 2014

December 2-3, 2014

NIOSH OIL & GAS EXTRACTION SAFETY & HEALTH PROGRAM

2007 2008 2009 2010 2011 2012 2013 2014 2015

Chemical Exposures to Oil & Gas Workers (EE, JS, MB)

Contact Injury Prevention Project (PS)

Motor Vehicle Best Practices in Oil & Gas (KR)

Preventing Fires & Explosions in Oil & Gas (JB)

Injuries in the Offshore Oil & Gas Industry (RH)

Preventing Falls in Oil & Gas (PS)

PPE Use in O&G: Seat Belts & Fall Protection (NM)

Rig Move Safety for Oil & Gas Workers (EC)

Projects

NORA Projects

PHP Projects

Chemical Exposures to O&G Workers (MB)

Presenter

Presentation Notes

NIOSH has had an active program of OH&S research in O&G since 2005 Projects are listed above the timeline, outputs listed below the timeline. Research program was built on NORA funds (except for the Chemical exposures work) Wide variety of outputs including scientific articles, videos, and numerous conference presentations, too many to list

December 2-3, 2014

NIOSH OIL & GAS EXTRACTION SAFETY & HEALTH PROGRAM

2007 2008 2009 2010 2011 2012 2013 2014 2015

SPE Article: Fatalities by Company Type

and Size

MMWR: Fatalities Among O&G

Workers Take Pride in Your Job: Seat Belts & Fall

Protection

Fact Sheet: Chemical Exposures to O&G

Workers

Move It! Rig Move Safety for

Roughnecks

SPE Article: Mortality Statistics for the US Upstream Industry

Well Servicing: Fatal Injuries in the

Upstream O&G Industry

ASSE Professional Safety:

Effective Training, A Case Study from the

O&G Industry

Move It! Rig Move Safety for Truckers

Publications

DVDs

JOEH Article: Occupational Exposures to Respirable Crystalline Silica during Hydraulic

Fracturing

SPE Article: Review of the Literature: MV

Safety Practices

Well Servicing: Understanding Silica Exposure Risks and

Controls

Synergist: Keeping Up with the Oil and

Gas Rush

NIOSH Science Blog: Reports of Worker Fatalities during

Flowback Operations

Online

NIOSH Science Blog: Preliminary Field Studies on

Worker Exposures to Volatile Chemicals during Oil and Gas

Extraction Flowback and Production Testing

Operations

JOEH Case Study: Evaluation of Some Potential Chemical

Exposure Risks during Flowback Operations in Unconventional Oil and

Gas Extraction

NIOSH Science Blog: Worker Exposures to

Crystalline Silica during Hydraulic

Fracturing

Outputs

Presenter

Presentation Notes

NIOSH has had an active program of OH&S research in O&G since 2005 Projects are listed above the timeline, outputs listed below the timeline. Research program was built on NORA funds (except for the Chemical exposures work) Wide variety of outputs including scientific articles, videos, and numerous conference presentations, too many to list

Bakken

Eagle Ford

Sites: 5 states, 11 locations, 15 months

Eagle Ford

Bakken

December 2-3, 2014

Presenter

Presentation Notes

Systematic evaluations of risks for silica exposures occurred at 11 sites in 6 states over a 15 month period: study was representative of a wide variety of conditions and site locations

December 2-3, 2014

Presenter

Presentation Notes

Describe the process of HF to audiences not familiar with the process using slide as reference

Sand Use in Hydraulic Fracturing • Silica sand = proppant • Hundreds of thousands lbs. per stage • > 90% of all oil and gas wells HF • Virtually 100% quartz • Workers in close

proximity to dust generation

December 2-3, 2014

Presenter

Presentation Notes

Increasing amounts of silica sand are used as proppant in modern wells, alternatives include ceramics and sintered bauxite but costs can be 7 fold as much as sand

Respirable crystalline silica (RCS): exposure risks from multiple sources during hydraulic fracturing

1. Release from top hatches, sand movers

2. Transfer belt under sand movers

3. Site traffic 4. Sand dropping in

blender hopper 5. Release from T-

belt operations 6. Release from

“dragon’s tail” 7. Dust ejected

from fill ports on sand movers

8. “Pig Pen” effect

Presenter

Presentation Notes

NIOSH research has identified at least 8 point of silica dust generation

Thief Hatches: Release of Silica Dust

Sand mover

Multiple sandmovers delivering sand to transfer belt, visible dusts suggests workplace exposure risks for RCS

Presenter

Presentation Notes

Emissions from thief hatches constitute a primary point source

Sand loading operations: thief hatch emissions, 2008

December 2-3, 2014

Presenter

Presentation Notes

Emphasize that in 2008 it was common (at least in CO in the Piceance basin) to observe only one sand mover on site

December 2-3, 2014

Sand loading operations: loading multiple sandmovers, 2011

Presenter

Presentation Notes

In 2011, it was common to see multiple sand movers, being filled serially or in some cases simultaneously (more silica sand being used, more aerosol generation)

ACGIH TLV : 0.025 mg/m3

NIOSH REL: 0.050 mg/m3

OSHA: 10 mg/m3

(% silica + 2)

December 2-3, 2014

Silica exposures at hydraulic fracturing sites can exceed OEL’s 1

Site > ACGIH TLV > NIOSH REL > OSHA PEL Total # samples

A 24 (92.3%) 19 (73.1%) 14 (53.9%) 26 B 16 (84.2%) 14 (73.7%) 12 (63.2%) 19 C 5 (62.5%) 5 (62.5%) 4 (50.0%) 8 D 19 (90.5%) 14 (66.7%) 9 (42.9%) 21 E 25 (92.6%) 23 (85.2%) 18 (66.7%) 27 F 4 (40%) 1 (10%) 0 10

Total 93 (83.8%) 76 (68.5%) 57 (51.4%) 111 1 Esswein, Breitenstein, Snawder, et.al,. Occupational Exposures to Respirable Crystalline Silica in Hydraulic Fracturing Jour. Occ. Env. Hyg. Vol. 10, Issue 7, May, 2013

December 2-3, 2014

Relative comparisons, geometric means (GMs) (mg/m3 ) by job title, OSHA PEL and NIOSH REL

00.05

0.10.15

0.20.25

0.30.35

NIOSH REL

OSHA PEL

Presenter

Presentation Notes

Workers closer to point sources with higher emissions have greater risks for exposures

Comparisons, respirable silica GMs (mg/m3), 95% confidence intervals, job titles with 5 or more samples

December 2-3, 2014

Presenter

Presentation Notes

Slide shows statistically significant differences between six different job titles

How much respirable crystalline silica is the NIOSH REL?

500 micrograms (µg’s)

Photo: Geoff Plumlee, USGS

NIOSH REL = 0.05 mg/m3 TWA

0.05 mg/m3 = 50 micrograms (µg)/m3

1 m3 of air = 1,000 liters

Normal breathing rate (moderate work, 1 work day) = 10 m3 (10,000 liters of air)

50 µg/m3 x 10 m3 = 500 µg’s

December 2-3, 2014

• Workers typically use respirators for protection

• Exposures can exceed respirator assigned protection factor

• Practical engineering controls for silica are needed

December 2-3, 2014

Job Title

Total # of samples

Arithmetic Mean

NIOSH REL

Arithmetic Std.

Deviation

Min

Max

Median

Blender Operator 16 2.58 0.59 0.14 9.70 2.03

Chemical Truck Operator 3 3.32 1.63 0.80 6.38 2.78

Fueler 2 0.85 0.17 0.68 1.02 0.85

Hydration Unit Operator 5 4.28 2.79 0.18 14.92 0.88

Mechanic 3 1.20 0.39 0.46 1.76 1.38

Operator, Data Van 1 0.86 ---2 0.86 0.86 0.86

Pump Truck Operator 1 0.42 --- 0.42 0.42 0.42

Q.C. Tech 1 0.26 --- 0.26 0.26 0.26

Roving Operator 4 0.52 0.24 0.12 1.18 0.39

Sand Coordinator 10 1.60 0.57 0.34 6.52 1.22

Sand Truck Driver 1 0.82 --- 0.82 0.82 0.82

Sandmover Operator 50 10.44 1.59 0.14 55.10 7.62

T-belt Operator 6 14.55 7.57 0.30 51.40 9.06

Water Tank Operator 7 1.23 0.34 0.38 2.72 1.12

Wireline Operator 1 0.14 --- 0.14 0.14 0.14

Total 111 6.45 0.93 0.12 55.10 2.18

Why respirators are not the answer: severities > 10, 50 X REL

December 2-3, 2014

Presenter

Presentation Notes

Boxes highlighted in yellow show NIOSH calculated severities (exposure divided by REL) severities > 1 exceed the REL Assigned protection factor (APF) for half masks and FF respirators = 10 APF for full face respirator = 50 Mean of samples for sandmover operators and T-belt operators > 10, max (1 sample each) for same > 50X NIOSH REL

NIOSH Mini-Baghouse Retrofit Assembly

Computer rendering: Kenneth Strunk, NIOSH, OMSHR December 2-3, 2014

NIOSH Mini Baghouse Retrofit Assembly Proof of concept, June 2012 Patent pending Fills immediate need: engineering control for silica dust A “bolt on control” No need to remove the sand mover from the field

2012 2014

Presenter

Presentation Notes

Beta version of mini baghouse evaluated in 2012, 4 prototypes built in-house in 2013 and evaluated in 2014

Sampling Methodology

• NMAM 0600 (resp. particulates) • NMAM 7500 (crystalline silica) • 37 mm polystyrene cassettes,

5 µm pore-size PVC filters • SKC XR 5000 sampling pumps • BGI GK 2.69 size selective

cyclones • Sampling trains: 4.2 LPM • 12 sampling locations

December 2-3, 2014

Plan view: 12 area sampling locations, FS-30 Sandmover 1-6 atop mover , A-F breathing zone height, ground

Computer rendering: Kenneth Strunk, NIOSH, OMSHR

December 2-3, 2014

Presenter

Presentation Notes

Rendering (bird’s eye or plan view) of sandmover, with 12 sampling locations identified

Methodology, con’d. • Bins 2 & 3 randomly selected for filling

• 8 “runs”, control on + off • 192 samples

• 96 samples control on • 96 samples control off

• Sampling time: 23-53 minutes

December 2-3, 2014

Presenter

Presentation Notes

Mini baghouses were attached to all 8 thief hatches to contain possible dust emissions as bins in sand mover have transfer grilles (air and dust can move between bins) Bins 2 and 3 were randomly selected (random number generator) for evaluation Fill time for a bin was between 23 and 53 minutes with controls attached and absent

8 runs, control on + control off bins 2 & 3

NIOSH mini baghouse retrofit assembly

December 2-3, 2014

Control on Control off

December 2-3, 2014

Presenter

Presentation Notes

Photo showing mini baghouse control on bin 3 and absent

December 2-3, 2014


Presenter

Presentation Notes

Control on bin 3 and not attached to same

December 2-3, 2014


Final run, 4 bins filled simultaneously

December 2-3, 2014

Presenter

Presentation Notes

Final evaluation (not included in statistical evaluation) to see what would happen if all 4 bins were filled at the same time

Results: respirable particulates, top of mover, downwind of emissions

Sampling Location

Dust Geometric Standard Deviation (mg/m3)

Dust Geometric

Mean – control off (mg/m3)

Dust Geometric

Mean – control on (mg/m3)

Ratio of Geometric Means with Control off

and on Reduction

(%)

3 5.44733 1.49374 0.15100 0.10109 89.8912

4 2.84553 9.68443 0.23702 0.02447 97.5525

5 4.31093 0.72609 0.04721 0.06502 93.4979

6 3.40334 0.51260 0.07819 0.15253 84.7473

Range: 84.7% – 97.6% reduction

December 2-3, 2014

Presenter

Presentation Notes

Of the 12 locations, the 4 locations listed (3-6 atop the sand mover) were downwind of the thief hatches and had consistent values > LOD, other locations were upwind or did not have enough values > LOD for statistical comparisons

Results: respirable crystalline silica top of mover, downwind of emissions

Sampling Location

Crystalline Silica

Geometric Standard Deviation (mg/m3)

Crystalline Silica

Geometric Mean –

control off (mg/m3)

Crystalline Silica

Geometric Mean –

control on (mg/m3)

Ratio of Geometric Means with Control off

and on Reduction

(%)

3 5.41435 0.43349 0.089956 0.20752 79.2484

4 3.39891 4.05456 0.053342 0.01316 98.6844

5 3.14646 0.33190 0.025750 0.07758 92.2417

6 3.63901 0.19814 0.032180 0.16241 83.7591

Range: 79.2 – 98.7% reduction

December 2-3, 2014

Results: bulk dust analysis

• Consistency of talcum powder • Light tan, “buff” color • Highly respirable • Origin: Quartz sand proppant (40/70 mesh) • Particle disintegration: pneumatic transfer

December 2-3, 2014

Presenter

Presentation Notes

The energy imparted to the sand during pneumatic transfer causes a portion of the sand to disintegrate, creating freshly fractured quartz fines.

Analysis of bulk dust, scanning electron microscope (SEM) + Gresham light element detector and IXRF digital imaging system.

72.4% of particles > 0.5 < 5 µm

Particle size distribution, silica dust collected by NIOSH mini baghouse retrofit assembly

greatest mass of silica particles between 1 and < 2 µm

0.0%

5.0%

10.0%

15.0%

20.0%

25.0%

30.0%

35.0%

<0.5 µm 0.5-<1µm

1-<2 µm 2-<3 µm 3-<5 µm 5-<10 µm 10-20 µm >20 µm

6.3%

25.0%

30.6%

13.0%

8.8% 9.2%

3.5% 3.5%

PERCENT IN EACH

SIZE RANGE

SiO2 Bulk Sample

December 2-3, 2014

Presenter

Presentation Notes

We collected bulk dust retained by the mini baghouse and had it analyzed for particle size distribution

“Sample contained a wide range of particle sizes from 0.1 µm to 7 µm.”

5µm

0.1 µm

SEM images Diane Schwegler-Berry, M.S. , Walter McKinney, M.S.E.E., NIOSH, HELD

“Some larger particles showed sharp points that evidenced no wear and were freshly broken.”

December 2-3, 2014

Scanning Electron Microscopy – airborne silica dust, collected 11/2013

Respirable dust < 10 microns (µm) SEM images: Art Miller, Ph.D, NIOSH

SEM image: Art Miller, Ph.D, NIOSH, OMSHR

December 2-3, 2014

Presenter

Presentation Notes

Art Miller walked through the aerosol cloud released during an uncontrolled run and collected an air sample which he later analyzed using SEM microspy

Examples of a small silica particles, approx. 100 nm.

Near nano-sized crystalline silica particles

SEM images Diane Schwegler-Berry, M.S. , Walter McKinney, M.S.E.E., NIOSH, HELD

Presenter

Presentation Notes

Some silica particles were determined to be approximately 100 nanometers (background showing holes is the filter)

Conclusions 1) NIOSH mini baghouse retrofit assembly demonstrates effective

control of respirable aerosols generated during sand filling 2) Silica aerosols generated during sand delivery operations are

highly respirable 3) Highly respirable silica dust also freshly fractured; more toxic than

aged quartz 1.

4) Large fraction of sub-micron and some nano-size particles suggest even higher toxicity

5) Adoption of engineering controls needed: limit, contain and control exposures

1. Vallyathan, V., Castranova, V. et. al., Freshly Fractured Quartz Leads to Enhanced Lung Injury and Inflammation, Potential Role of Free Radicals. Am. Jour. Resp. Crit. Care Med. Vol. 152. 1995

December 2-3, 2014

QUESTIONS?

December 2-3, 2014

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