RISK ASSESSMENT OF OCCUPATIONAL CHEMICAL EXPOSURES TO HYDRAULIC FRACTURING FLUIDS

SPECIAL PROJECT

SUMMER, 2012

Brooke Fait, P.G

RISK ASSESSMENT OF OCCUPATIONAL CHEMICAL EXPOSURES TO HYDRAULIC FRACTURING FLUIDS

Well stimulation is a practice used to increase production in a natural reservoir by increasing the permeability of a rock formation. Well stimulation in “conventional” extraction of oil, natural gas, and groundwater wells (extraction from confined high porosity media; sandstone and limestone formations [Hanlon, 2011]) was reportedly first developed by Herman Fraschin in 1895 (Knox, 1973) with the first hydraulic fracturing (HF) developed by Halliburton in 1947 (Halliburton, 2012). The use of well stimulation for “unconventional” extraction (extraction from low porosity media; subsurface silt, shale, and mudstone) is a consequence of technological advances and economic viability beginning in the 1980s with widespread practices occurring to the present.

This occupational exposure risk assessment of HF fluids is being performed in support of the National Occupational Research Agenda (NORA) “Strategic Goal 5: By 2020, identify hazards, characterize risk, and prevent chemical exposures, which could lead to occupational illness in workers in the oil and gas (O&G) extraction industry” by Surveillance Goal 5.2.3: “Identify existing and potential exposure threats and their impact on occupational illness, including chemical exposures, to workers in the oil and gas extraction industry. Use and organize existing databases, surveillance systems and other information” (NORA, 2011).

The first section of this report covers the national occupational employment estimates and trends in the U.S. oil and gas extraction industry by highlighting the Department of Labor (DOL) database under the Bureau of Labor Statistics (BLS) with graphs of National Occupational Employment Estimates Sector: 138 (Figure 1) and Sector: 1389 (Figure 2). The U.S. Energy Information System (EIS) graph of crude oil and natural gas exploratory and development wells drilled for the past three and a half decades is presented as Figure 3. The most recent quarterly census of employment and wages from the DOL is presented as Figure 4. The second section of the report presents the basic principles behind well hydraulic fracturing, followed by an industrial safety overview. The Occupational Safety and Health Administration (OSHA) IMIS database was used in conjunction with OSHA health alert factsheet to compare the top 10 cited OSHA violations among Industry Group 138. The Groundwater Protection Council (GWPC) FracFocus.org website was

used to identify the most commonly used hydraulic fracturing fluid additives currently in use: 2-butoxyethanol, acetaldehyde, acetic acid, ammonium persulfate, borate salts, boric acid, calcium chloride, choline chloride, citric acid, copolymer of acrylamide and sodium acrylate, crystalline silica (cristobalite), crystalline silica (quartz), ethanol, ethylene glycol, formic acid, glutaraldehyde, guar gum, hydrochloric acid, hydrotreated light petroleum distillate, isopropanol, lauryl sulfate, magnesium oxide, magnesium peroxide, methanol, naphthalene, non-crystalline silica, petroleum distillate, phosphonic acid salt, poly (oxy-1,2-ethanediyl), polyacrylamide, polysaccharide blend, potassium carbonate, potassium hydroxide, potassium metaborate, quaternary ammonium chloride, quaternary ammonium chloride, sodium carbonate, sodium chloride, sodium chloride, sodium erythorbate, sodium hydroxide, sodium polycarboxylate, sodium tetraborate, tetrakis hydroxymethyl-phosphonium sulfate, tetramethyl ammonium chloride, thioglycolic acid, triethanolamine zirconate, and zirconium complex. An electronic file containing an overview of the chemicals as provided from the Center for Disease Control (CDC) National Institute of Occupational Safety and Health (NIOSH) chemical database “NIOSH Pocket Guide” is presented as Appendix A for the 18 of the 47 chemical additives identified. The NIOSH Pocket Guide was also used to generate a summary of human health hazards presented as Appendix B. the U.S. Environmental Protection Agency (EPA) database “Scorecard Goodguide” was used to evaluate the human health hazards of 26 of the identified chemical additives. The International Chemical Safety Cards (ICSC) database was used to present exposure limits and effects of exposure for 32 of the 47 most commonly used chemicals in hydraulic fracturing operations presented as Appendix C. A table of the quantity estimate of hydraulic fracturing fluid additives is presented as Table 2. Workplace monitoring and measurement sample results and available statistics is reviewed using recent OSHA/NIOSH hazard alert factsheet and voluntary incident reporting summarized and presented by the International Association of Drilling Contractors (IADC). Specific safety recommendations are provided including 3M industry chemical specific respiratory recommendations and odor threshold data presented as Table 3. General conclusions regarding further monitoring and safety practices are presented in the final section.

The challenges of conducting a risk assessment of occupational chemical exposures to hydraulic fracturing fluids are derived from the lack of standardization and comprehensive reporting. Standardization of application is not feasible given that chemical application is dependent on the variability from each well site based on geology, geochemistry, temperature, pressure, depth, wellbore distance, and even fluid supply concentrations and availability. Procedures, training, and equipment also vary from site to site. Reporting has been limited by use of proprietary data, attorney client privilege (Coleman, 2011), spill and other release data availability (EI, 2012), and limited non-fatal occupational injuries and illnesses data reporting (NORA, 2011).

Source materials for this occupational chemical exposure risk assessment include; existing databases: CDC, EIA, ICSC, IMIS, and Scorecard; surveillance systems: BLS/DOL, EPA, GWPC, NIOSH, and OSHA; and other information such as: Local and Federal Government whitepapers and presentations, O&G industry websites, O&G industry whitepapers and presentations, Research Institution whitepapers and presentations, the International Association of Drilling Contractors, and the Society of Petroleum Engineers Library.

NATIONAL OCCUPATIONAL EMPLOYMENT ESTIMATES AND TRENDS IN THE U.S. OIL AND GAS EXTRACTION A Bureau of Labor Statistics (BLS) comparison of Industry Group 138 (drilling, exploration, field support) to Oil and Gas Field Services (SIC 1389 field support) shows employment for field support tasks accounted for more than half of the overall employment totals for the time period 1997 to the year 2000. The Bureau of Labor Statistics limits employment census searches by standard industry codes to 1997 through the year 2000. Figure 1 National Occupational Employment Estimates Sector: 138 Series Id: EWUUS0001050B138 State: U.S. TOTAL Area: U.S. TOTAL Industry: SIC 138 Oil and Gas Field Services Owner: Private Size: All establishment sizes Type: All Employees

Quarterly Census of Employment and Wages (SIC)138 http://data.bls.gov/pdq/SurveyOutputServlet

Figure 2 National Occupational Employment Estimates Sector 1389

Series Id: EWUUS0001050B1389 State: U.S. TOTAL Area: U.S. TOTAL Industry: SIC 1389 Oil and gas field services, nec Owner: Private Size: All establishment sizes Type: All Employees

DOL Quarterly Census of Employment and Wages (SIC) 1389 http://data.bls.gov/pdq/SurveyOutputServlet

The U.S. Energy Information System graph of Crude oil and Natural gas exploratory and development wells drilled for the past three and a half decades reflect the employment census dip in 1999 with a similar decrease in well development. High exploration and development data can also be observed for the 1980’s oil and gas boom as well as the last decade increase in overall exploration and development. Hydraulic fracturing has become commonplace throughout the O&G sector. Federal and industry estimates show “An estimated 11,400 new wells are fractured each year; EPA estimates another 1,400 existing wells are re-fractured to stimulate production or to produce natural gas from a different production zone” (EPA, 2012) and “nearly nine out of 10 onshore wells – natural gas and oil – require fracture stimulation to remain or become viable” (Halliburton, 2012).

Figure 3 Crude Oil and Natural Gas Exploratory and Development Wells

The BLS initiated the use of North American Industry Classification System (NAICS) codes in 2000, although SIC codes are still used including OSHA industry classifications. The most recent BLS data is provided in the April 2010 Fact Sheet for Oil and Gas Well Drilling which covers: oil and gas operators (211), which own the rights to drill for oil and gas; drilling contractors (213111), which drill oil and gas wells; and service companies (213112), which service oil and gas wells (BLS, 2010). The BLS Quarterly Census of Employment and Wages graph shows a decrease in employment consistent with the above exploration and development well construction associated with the 2009 recession related energy demand reduction. Natural disasters, and the Gulf oil spill disaster have also impacted production rates seen on the above graph, but production is estimated to increase in the future.

Figure 3 Crude Oil and Natural Gas Exploratory and Development Wells

Figure 4 Employment in drilling oil and gas wells 2001 to 2009

PRINCIPLES BEHIND WELL HYDRAULIC FRACTURING

Wells are subsurface conduits to natural resources, and like many conduits are subject to reduced flow capacity by source reservoir flow limitations and the accumulation of detritus during use. Well stimulation through the use of chemicals to remove naturally occurring barriers to hydraulic conductivity within the wellbore was first used 1895 (Knox, 1973). Halliburton further developed well stimulation technology in 1947 with hydraulic fracturing, using the process to stimulate flow of natural gas using high pressures (Halliburton, 2012). Hydraulic fracturing for subsurface natural resource recovery from formations with low permeability occurs through high pressure surface injection of water and chemical additives (generally following perforation of the wellbore) to promote and maintain induced dissolution and pressure fractures within the wellbore.

Standardization of HF fluids would not result in optimal performance of the well stimulation because geological units present unique conditions in each well site and the depths, pressures, temperatures, permeability, and geochemistry are highly

variable. The fact that HF chemical additives must be selected based on individual well assessments and performance criteria (in some instances amended during application) serves as a barrier to chemical reporting within the industry. Increased public concern over groundwater contamination has led to mandated disclosure of additives including the initiation of the FracFocus.org chemical disclosure registry website. The registry lists the most commonly used chemicals and served as the main source for the chemicals discussed within this risk assessment.

INDUSTRIAL SAFETY OVERVIEW

“The oil and gas extraction industry includes operations involved in the drilling and extraction of crude oil and natural gas, comprising the largest part of the U.S. mining industry. During 2003-2008, 648 oil and gas extraction workers were fatally injured on the job, resulting in an occupational fatality rate of 29.1 deaths per 100,000 workers – eight times higher than the rate for all U.S. workers. Significant gaps exist in the availability of non-fatal occupational injuries and illnesses data for the oil and gas extraction industry” (NORA, 2011). “Support activities for oil and gas operations (NAICS 213112) account for about half of fatal work injuries from 2004 to 2008 in oil and gas industries on average, with 69 fatal work injuries recorded in 2008. Fatal injury data include oil and gas extraction, drilling oil and gas wells, and support activities for oil and gas extraction. Nonfatal injury and illness data only include drilling oil and gas wells”( BLS, 2010).

The top 10 violations for Oil and Gas field service providers cited by OSHA have changed from 2005 to 2010 (Table 1). This shows failure to comply with reporting requirements are increasingly being cited (highlighted in red). Both 1904 standard violations were cited 16 times out of 4 inspections with penalties totaling $97, 200 for injury and illness summary violations and $95,200 for access to records violations. Hazard Communication 1910.1200 standard was cited 62 times out of 35 inspections in 2005 compared with 23 citations out of 14 inspections in 2010 which led to penalties totaling $27,225. General Personal Protective Equipment 1910.132 standard was cited 42 times out of 30 inspections in 2005 compared with 31 citations out of 25 inspections in 2010 which led to penalties totaling $72,410. Respiratory Protection 1910.134 standard was cited 39 times out of 11 inspections in 2005 compared with 24 citations out of 6 inspections in 2010 which led to penalties totaling $20,006. Citations for hazard communication has dropped from

the number one spot in 2005 (frequency=1.7) to number six for 2010 (frequency=1.6); it remains a major concern but the change may demonstrate the O&G support services efforts to improve availability of safety data sheets in field operations. Table 1: Top 10 Violations Cited by OSHA for Division B: Mining

Major Group 13: Oil and Gas Extraction, Industry Group 138

Standard Violation 20051 Standard Violation 20102

1 Hazard Communication Permit-required confined spaces

2

Permit-Required Confined Spaces

Personal Protective Equipment, General requirements.

3

General Duty Clause (Section of OSHA Act)

General Duty Clause (Section of OSHA Act)

4

Personal Protective Equipment, General requirements.

Guarding floor and wall openings and holes.

5

Wiring Methods, Components, and Equip. for General Use

Respiratory Protection.

6

Guarding Floor & Wall Openings & Holes

Hazard Communication.

7 Respiratory Protection General requirements. Electrical

8 Medical Services & First Aid Wiring methods, components, and equipment for general use.

9 Sanitation Recording criteria. 10 Portable Fire Extinguishers General recording criteria.

1IMIS Database – FY 2005 (Federal only). Industry Group 138 including SIC 1381 – Drilling Oil and Gas Wells; SIC 1382 – Oil and Gas Field Exploration Services; and SIC 1389 Oil and Gas Field Services, Not Elsewhere Classified. (OSHA, 2006)

2http://www.osha.gov/pls/imis/citedstandard.sic?p_esize=&p_state=FEFederal&p_sic=1389. Standard Violations were cited by Federal OSHA for SIC 1389 during the period October 2010 through September 2011 for Division B: Mining Major Group 13: Oil And Gas Extraction Industry Group 138: Oil And Gas Field Services 1389 Oil and Gas Field Services, Not Elsewhere Classified Establishments primarily engaged in performing oil and gas field services, not elsewhere classified, for others on a contract or fee basis. Services included are excavating slush pits and cellars; gradings and building of foundations at well locations; well surveying; running, cutting, and pulling casings tubes, and rods; cementing wells; shooting wells; perforating well casings; acidizing and chemically treating wells; and cleaning out, bailing, and swabbing wells. Establishments which have complete responsibility for operating oil and gas wells for others on a contract or fee basis are classified according to the product extracted rather than as oil and gas field services. Establishments primarily engaged in hauling oil and gas field supplies and equipment or primarily engaged in oil and gas field machine shop work are classified elsewhere http://www.osha.gov/pls/imis/sic_manual.display?id=391&tab=description

OVERVIEW OF CHEMICALS

HF fluids contain chemical additives which are generally organized into different functional groups: Acid, Biocide, Corrosion Inhibitor, Iron Control, Proppant, Friction Reducer, Gel, Crosslinker, Breaker, KCl, pH Adjusting Agent, Scale Inhibitor, and Surfactant (GWPC, 2009). Several of these chemical additives are unique to the HF procedure (Breaker, Crosslinker, Friction Reducer, Gel, pH Adjusting Agent, Proppant) while others are used throughout the industry for conventional well stimulation (Acid, Biocide, Corrosion Inhibitor, Iron Control, KCl, Scale Inhibitor, and Surfactant). Applications of HF chemical additives are also being used as preventative measures for production related issues of scale and organic matter pipe accumulation and deposition (Al-Qami, 2011). Only the chemicals presented as the most commonly used on the fracfocus.org website with the addition of proppants are discussed in this risk assessment. Appendix A: Overview Of Chemicals provides specific chemical data including synonyms and physical data available from the CDC database NIOSH Pocket Guide.

The acid stage prepares the wellbore for hydraulic fracturing by dissolving minerals and initiating cracks and opening fractures in the formation. Acid also serves to clear cement debris in the wellbore and provide an open conduit for other HF fluids by dissolving carbonate minerals (GWPC, 2012).

Biocides (glutaraldehyde, ammonium chloride, bromine-based solutions) are used to prevent microbiological growth within the well by disinfecting and sterilizing water introduced in the HF process (GWPC, 2009). Bacterial growth may corrode pipe, produce hydrogen sulfide known to “sour” the formation, and create production flow restrictions. The introduced source water may be derived from ground water, surface water, and re-use of HF fluids termed produced water. The “biocide is added in a liquid form to the water pumped downhole” where the amount of biocide added is based on the level of bacteria measured in the water (Degner, 2011).

Similar to biocides, corrosion inhibitors and iron control/stabilizing agents prevent pipe corrosion and flow restrictions. Common corrosion inhibitors include N,n-dimethyl formamide and ammonium bisulfate used as an oxygen scavenger. Citric

acid or hydrochloric acid is commonly used to keep soluble iron compounds from precipitating (GWPC, 2009). Proppants (silica, quartz sand) keep or “prop” open the newly formed pressure fractures increasing the permeability of the “pay zone”. Production formations may lie between 1 to 2 miles below the surface under high pressure. Proppants allow the anthropogenically induced permeability to be maintained after the pressure treatment is complete. The grain sizes of the proppants are increased throughout the HF sub-stages (GWPC, 2009). Early sub-stages may introduce a 100 mesh (~150 microns) proppant followed by a 40/70 and 20/40 mesh (fine sand) grain size. Silica sand is generally used but ceramic “Black-Cat” or sintered bauxite has been applied in high pressure, deep well formations (OSHA, 2012).

Friction reducers (FR) increase the fluid viscosity (close to that of water [< 5 cps]) to reduce surface pressures required to transport the HF treatment to the deep (~10,000 ft wellbore) subsurface (Degner, 2011). “FR often comes from the manufacturer in dry powder form, but is most commonly pumped as a liquid by mixing with a mineral oil base fluid to stabilize the material until it’s injected into the water stream and pumped downhole” (Degner, 2011). The FR component (potassium chloride or polyacrylamide-based compounds) “may reduce tubular friction by 50 to 60%” earning the designation of slick-water (GWPC, 2012).

Gel and KCl additives are used to carry the proppant to the facture zones. Crosslinker additives enhance the transport capacity of the gel by maintaining low viscosity with increased hydrothermal and friction temperature increases while pH adjusting agents maintain the effectiveness of the crosslinkers. Breakers allow for the subsurface breakdown of the carrier fluids leaving the proppant in place (GWPC, 2009). The addition of scale inhibitor, such as ethylene glycol, prevents flow restrictions due to the buildup of calcium carbonate and barium sulfate precipitates (GWPC, 2012). Scale inhibitors are added in larger quantities in the later sub-stages of the HF treatment as the fluids mobilize more dissolved solids from the formation. Solvent based additives inhibit scale formation which requires chemical (HCl removal of calcium carbonate) or mechanical (well swabbing removal of barium

Sulfate) remediation (Degner, 2011).

Surfactant use serves a few product functions. Surfactants can be used to “reduce surface tension on the fracture face making it easier to recover produced fluids” (Degner, 2011). Surfactants (such as Isopropanol) may also be used to increase HF treatment fluid viscosity (GWPC, 2009).

HUMAN HEALTH HAZARDS

A summary of human health hazards associated with the most commonly used hydraulic fracturing chemical additives is provided as Appendix B. The summary table includes the NIOSH recommended exposure limit (REL), target organs, and exposure symptoms.

Human health hazard summaries of recognized (by authoritative scientific organizations) and suspected (on the basis of more limited data) health hazards are also available from the scorecard pollution information site (Goodguide, 2011). A chemical-profile summary was available for 26 of the 47 most commonly used chemicals in hydraulic fracturing operations (http://scorecard.goodguide.com).

Acetaldehyde and naphthalene (per California state, proposition 65), are the only chemicals with a recognized adverse health effect found on the Goodguide data base though inadequate evidence in humans has led to the international agency for research on cancer group 2B: possible human carcinogen (sufficient evidence in animals) classification (Goodguide, 2011). Crystalline silica and ethanol are listed as suspected carcinogens.

Ethanol and 2-butoxyethanol are suspected of endocrine toxicity. Seven additives are suspected of developmental toxicity: glutaraldehyde, isopropanol, methanol, ethanol acetaldehyde, ethylene glycol, naphthalene, and 2-butoxyethanol. Five additives are suspected of reproductive toxicity: glutaraldehyde, ethylene glycol, ethanol, boric acid, and 2-butoxyethanol.

Twelve additives are suspected of cardiovascular or blood toxicity: ammonium chloride (fume), isopropanol, ethanol, formic acid, acetic acid, ethylene glycol, sodium tetraborate, boric acid, sodium chloride, calcium chloride, naphthalene, and

2-butoxyethanol. Four additives are suspected of neurotoxicity isopropanol, methanol, ethanol, and naphthalene.

Seven additives are suspected of gastrointestinal or liver toxicity hydrochloric acid, isopropanol, methanol, ethanol, formic acid, acetic acid, ethylene glycol, sodium tetraborate, boric acid, sodium chloride, lauryl sulfate, naphthalene, 2-butoxyethanol. Seven additives are suspected of kidney toxicity: isopropanol, methanol, formic acid, acetaldehyde , ethylene glycol, boric acid, 2-butoxyethanol

Hydrochloric acid is suspected of musculoskeletal toxicity. Four additives are suspected of immunotoxicity: hydrochloric acid, glutaraldehyde, acetaldehyde,and ammonium persulfate.

Fifteen additives are suspected of respiratory toxicity: hydrochloric acid, glutaraldehyde, isopropanol, methanol, ethanol, formic acid, acetaldehyde, acetic acid, crystalline silica, ethylene glycol, boric acid, sodium hydroxide, sodium carbonate, ammonium persulfate, and naphthalene. Fifteen additives are suspected of skin or sense organ toxicity: hydrochloric acid, glutaraldehyde, isopropanol, methanol, ethanol, formic acid, acetaldehyde, acetic acid, ethylene glycol, boric acid, sodium hydroxide, potassium hydroxide, ammonium persulfate, naphthalene, and 2-butoxyethanol.

EXPOSURE LIMITS and EFFECTS OF EXPOSURE

All available exposure limits and effects of exposure data are summarized from: http://www.ilo.org/dyn/icsc/showcard.home International Chemical Safety Cards (ICSC), European Commission (CEC) or the International Programme on Chemical Safety (IPCS) database and presented in Appendix C. Available acute exposure, chronic exposure effects, reproductive or developmental effects, and cancer risk are summarized for 32 of the 47 most commonly used chemicals in hydraulic fracturing operations.

Chemicals which were not available from this source include two biocides: quaternary ammonium chloride, tetrakis hydroxymethyl-phosphonium sulfate; one iron control: sodium erythorbate; one friction reducer: polyacrylamide; two gelling agents: polysaccharide blend, guar gum; three crosslinkers: potassium metaborate,

triethanolamine zirconate, zirconium complex; two of the breakers: sodium chloride and magnesium peroxide; the non-crystalline silica proppant; and all three of the scale inhibitors: copolymer of acrylamide, sodium acrylate, and sodium polycarboxylate, phosphonic acid salt.

Chemical exposure is highly dependent on the individual chemicals selected for addition into hydraulic fracturing fluids, the method of decantation or addition, type of storage containers, the equipment used for mixing and dilution, concentrations of the chemical additives, engineering controls, and personal protection equipment usage. Biological monitoring is presented under Recommendations.

HF chemical “additives are transported in concentrated forms and diluted when pumped” with reported blended concentrations of 3:1,000 gallons (Halliburton, 2011). The traffic burden created by the mobilization of equipment and supplies often rivals urban high volume where “one estimate indicates a need for 100 to 150 truckloads of hydraulic fracturing equipment and another 100 to 1,000 loads for the fracturing fluid and sand for proppants (when trucks rather than pipelines are used)” (EI, 2012). To understand the amount of chemicals used within a HF well stimulation the following table was adapted using the percentages of additive and the generalized single stage pumping volume (578,000 gallons) from Modern Shale and Gas Development in the United States: A Primer prepared for the U.S. Department of Energy, Office of Fossil Energy and National Energy Technology Laboratory by Oklahoma based Ground Water Protection Council (GWPC, 2009). It should be noted that the table quantities reflect 1/3 the previously mentioned Halliburton estimate and as many as 40 stages may be completed on one well.

Table 2 Quantity Estimate of Hydraulic Fracturing Fluid Additives

Product Function

Percent by Volume

One Stage (gallons)

Four Stages (gallons)

Seven Stages (gallons)

Ten Stages (gallons)

Fifteen Stages (gallons)

Acid 0.123 711 2,844 4,977 7,109 10,664 Biocide 0.001 6 23 40 58 87 Breaker 0.01 58 231 405 578 867 Corrosion Inhibitor 0.002 12 46 81 116 173 Crosslinker 0.007 40 162 283 405 607 Friction Reducer 0.088 509 2,035 3,560 5,086 7,630 Gel 0.056 324 1,295 2,266 3,237 4,855 Iron Control 0.004 23 92 162 231 347 KCl 0.06 347 1,387 2,428 3,468 5,202 pH Adjusting Agent 0.011 64 254 445 636 954 Proppant * 9.5 54,910 219,640 384,370 549,100 823,650 Scale Inhibitor 0.043 249 994 1,740 2,485 3,728 Surfactant 0.085 491 1,965 3,439 4,913 7,370

WORKPLACE MONITORING AND MEASUREMENT

Generally air monitoring is performed in compliance to 40 CFR Part 63 - National Emission Standards for Hazardous Air Pollutants for Source Categories (a.k.a. Maximum Achievable Control Technology (MACT)). Personalized breathing zone (PBZ) screenings are not generally performed and comprehensive data is lacking. A NIOSH field effort has been initiated to assess these chemical exposures associated with hydraulic fracturing. Initial sampling results have been published in the joint OSHA and NIOSH Hazard Alert for airborne silica exposure. The multi state, multi site, occupational exposure sampling showed PBZ air samples to be in excess of the OSHA PEL in 47% of the 116 samples collected with 9% of samples in excess of 10 times the PEL (NIOSH, 2012).

The International Association of Drilling Contractors provides an annual summary of Occupational Incidents. Roughly half of the largest drilling support service

companies participate in the voluntary reporting of injury and illness data (though two of the top three [Halliburton and Baker Hughes] do not). The Incident Statistics Program produces annual reports which are divided into incident types. Of the 1412 US land operations total recordable incidents, chemical inhalation and contact with chemical/ fluids accounted for only 0.07% and 1.84% of recordable incidents respectively. In contrast, heat exhaustion/ heat stroke accounted for more total recordable incidents than chemical exposures combined at 3.05% of incidents reported. Statistically, workers are more than10 times as likely to be struck by (25.99%) or caught between/in (27.55%) tools and equipment than suffer a recordable incident associated with chemical exposure (IADC, 2012). However, it should be noted that actual HF operations may only account for approximately 5% (2 days out of 39 estimated) of a well installation schedule (Al-Qarni, 2011).

RECOMMENDATIONS

Chemical exposure is highly dependent on the individual chemicals selected for addition into hydraulic fracturing fluids, the method of decantation or addition, type of storage containers, the equipment and procedures used for mixing and dilution, concentrations of the chemical additives, engineering controls, administrative controls, training, and personal protection equipment usage.

Engineering controls should include: substitution of highly toxic chemicals; use of closed system material transport, mixing, storage, and dilution; reduction of concentrations of hazardous chemical additives delivered; utilize wet dust suppression and airborne dust capture systems.

Administrative controls should including: review work practices to identify high exposure risk operations and duties; ensure proper hazard communication; maintain equipment used for material handling of additives; test equipment for structural integrity especially where equipment modifications have been made; mandate screening and biomonitoring for known and suspected chemical exposures (as specified from ACGIH BEI tables) . NIOSH is currently recommending medical exams and chest X-ray screenings as follows: every three years if the employee has less than 15 years of silica exposure, every two years if the employee has 15 to 20 years of exposure, and every year if the employee has 20 or more years of exposure” (OSHA, 2012).

Chemical Name IDLH (PPM) OEL (PPM) Odor Threshold (PPM)

Respirator (to 10x OEL)

2-Butoxyethanol 700 TWA=20 0.001 (F)OV Acetaldehyde 10,000 TWA=200 (OSHA)

C=25 0.186 (F)OV

Acetic Acid 1,000 TWA=10 STEL=15

0.016 (F)OV

Boric Acid TWA=2 mg/m3 (inhalable fraction)

STEL=6 mg/m3 (inhalable fraction)

N95

Crystalline Silica (cristobalite),(quartz),

TWA=0.025 mg/m3 (respirable fraction)

N95

Ethanol 15,000 1000 STEL 0.136 OV Ethylene Glycol 32,000 C=100 mg/m3

(aerosol only) 60.3 mg/m3 OV/P95

Formic Acid 30 TWA=5 STEL=10

28.2 F(OV)

Glutaraldehyde C=0.05 0.038 F(OV) Hydrochloric Acid 100 C=2 0.77 AG

Isopropanol 12,000 TWA=200 STEL=400

0.44 F(OV)

Magnesium oxide fume

TWA=10 mg/m3 (inhalable fraction)

N95

Methanol 25,000 TWA=200 STEL=250-skin-

141 SA

Naphthalene 500 TWA=10 STEL=15-skin-

0.015 OV

Non-Crystalline Silica TWA=0.8 mg/m3 (OSHA)

N95

Petroleum Distillate as Stoddard solvent

29500 mg/m3 TWA=100 1-30 OV

Potassium Hydroxide C=2 mg/m3 N95 Ammonium Chloride TWA=10 mg/m3

STEL=20 mg/m3 N95

Sodium Hydroxide 250 mg/m3 C=2 mg/m3 N95 Sodium Tetraborate TWA=2 mg/m3

(inhalable fraction) STEL=6 mg/m3

(inhalable fraction)

N95

Thioglycolic acid 59,000 TWA=1-skin- F(OV) Zirconium and

compounds (as Zr) 7440-67-7

500 mg/m3 TWA=5 mg/m3 STEL=10 mg/m3

N95

(IDLH), Immediately Dangerous to Life or Health

(TWA) Time Weighted Average

(OEL) occupational exposure limit

(STEL) Short-Term Exposure Limit

(F) Full Facepiece (with appropriate cartridges and filters)

AG Acid Gas Respirator (C) Ceiling SA Supplied Air Respirator

N95 N95 Particulate Respirator

OV Organic Vapor Respirator

(3M, 2011) 2011 Respirator Selection Guide. 3M Occupational Health and Environmental Safety Division. April 2011 The primary references for odor thresholds were VOCBASE and an American Industrial Hygiene Association (AIHA) publication. The occupational exposure limits listed are 2009 ACGIH Threshold Limit Values (TLVs), IDLH Level-This is the concentration considered Immediately Dangerous to Life or Health (IDLH), as published by the National Institute for Occupational Safety and Health (NIOSH) (DHHS [NIOSH] Publication No.90-117). http://multimedia.3m.com/mws/mediawebserver?mwsId=SSSSSu7zK1fslxtUOxmG4x_Sev7qe17zHvTSevTSeSSSSSS--

Table 3 Chemical Specific Respiratory Recommendations

Personal protective equipment and personal hygiene procedures should be followed according to Safety Data Sheets. Adequate personal hygiene facilities should be provided to insure proper management and isolation of hazards. Table 3 Chemical Specific respiratory recommendations are presented as amended from the 3M 2011 Respirator Selection Guide. Both glutaraldehyde and formic acid are highlighted in red due to their very low occupational exposure limits and associated chemical odor thresholds (glutaraldehyde: odor threshold 0.038ppm/Ceiling Limit 0.05ppm) or exceeding recommended (formic acid: odor threshold 30 ppm/IDLH 28.2 ppm) (3M, 2011).

CONCLUSIONS

Improvements have been made in the disclosure and availability of chemical data for additives used in hydraulic fracturing operations (though by no means comprehensive) through increased regulation on chemical disclosure. Reporting data on releases, spills, and non-fatal occupational injuries and illnesses for the oil and gas extraction industry support activities remain inadequate. Existing databases show chemical evaluations for less than 2/3 of the most commonly used chemicals used in hydraulic fracturing.

Chemical exposure monitoring data are deficient but necessary for the protection of workers exposed to suspected human carcinogens, sensitizers, and toxins where uncontrolled exposures may occur. Substitution of these materials should be implemented where possible. Engineering controls to reduce airborne silica dust concentrations and biomonitoring are necessary.

Large quantities of additives pose a material handling risk, especially where open tank addition, dilution, and mixing of concentrated chemicals occurs on site. Equipment and procedures should be evaluated to insure worker safety. Hazard communication, respiratory protection, and general PPE usage are still in the top 10 of Federal OSHA violations for 2010 indicating further improvements must be made to insure exposure risks are managed in hydraulic fracturing operations.

REFERENCES

Ali O Al-Qarni et al, 2011. From Reservoir Specifics to Stimulation Solutions. Schlumberger Oilfield Review.

BLS, 2010. Fatal and Nonfatal Occupational Injuries Fact Sheet. Bureau of Labor Statistics U.S. Department of Labor. April 2010. Retrieved from: http://www.bls.gov/iif/oshwc/osh/os/osar0013.htm

Nancy Pees Coleman, Ph.D. 2011. Produced Formation Water Sample Results from Shale Plays. Environmental Consultants and Chesapeake Energy Corporation. Proceedings of the Technical Workshops for the Hydraulic Fracturing Study: Chemical & Analytical Methods, Arlington, Virginia. Publication No. EPA 600-R-11-066.

Dennis Degner. 2011. •HF Fluid Considerations in Marcellus Shale Completions. Proceedings of the Technical Workshops for the Hydraulic Fracturing Study: Chemical & Analytical Methods, Arlington, Virginia. Publication No. EPA 600-R-11-066.

EI, 2012. Fact-Based Regulation for Environmental Protection in Shale Gas Development. The Energy Institute. The University of Texas at Austin. February 2012. http://energy.utexas.

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