Saturday, August 25, 2018

Gases and vapors continue to pose hazards on oil and gas well sites during gauging, fluid transfer, and disposal




NIOSH Investigating Deaths Associated with Fracking Flowback Operations


Oil Well Drilling Fatalities

Though the investigations are not complete, NIOSH has learned about several worker fatalities associated with flowback operations. According to their information, at least four workers have died since 2010 from what appears to be acute chemical exposures during flowback operations at well sites in the Williston Basin (North Dakota and Montana).
fracking image.jpgThe available information suggests that these cases involved workers who were gauging flowback or production tanks or involved in transferring flowback fluids at the well site. Often these fatalities occurred when the workers were performing their duties alone.

Potential Exposures during Flowback Operations

Before a well begins producing, each horizontal well needs between 2.4 and 7.8 million gallons of freshwater.  This water is pumped from local water sources like streams and rivers and then mixed with chemicals and sand.   It is then injected into the well bore under high pressure. 
The force of this mixture is strong enough to fracture the shale to stimulate the flow of gas or oil.  As the gas or oil begins flowing, the mixture is pushed back up along with other substances picked up from deep underground like heavy metals, brine, naturally occurring radioactivity from uranium and volatile hydrocarbons.
Flowback refers to this process of the fluids from the wellbore which return to the surface and are collected after hydraulic fracturing is completed. After separation, flowback fluids are typically stored temporarily in tanks or surface impoundments (lined pits, ponds) at the well site. Liquid hydrocarbons from the separation process are routed to production tanks where they must be stored and then disposed of. Workers periodically gauge the fluid levels in flowback and production tanks with hand-held gauges (sticks and tapes) through access hatches located on the top of the tank.
Some problems which need to be addressed are the potential and occurrence of tears in linings, spills, and leaks in the waste storage tanks and ponds.  In addition to the onsite problems, local sewage treatment plants and landfills are often not equipped to test for and handle this amount of waste infused with salts, metals, and solvents.
Hydrogen sulfide (sour gas) is well recognized as a toxic exposure hazard associated with oil and gas extraction and production. However, less recognized by many employers and workers is that many of the chemicals found in volatile hydrocarbons are acutely toxic at high concentrations.
Recently, NIOSH conducted exposure assessments to identify chemical hazards to workers involved in flowback operations.
Results from initial field studies suggest that certain flowback operations/activities can result in elevated concentrations of volatile hydrocarbons in the work environment that could be acute exposure hazards.  Volatile hydrocarbons have been found to affect the eyes, breathing, and the nervous system and at high concentrations may also affect the heart causing abnormal rhythms.
Toxic inhalation and chemical exposure injuries are serious. Workers Compensation may provide some remuneration for such injuries, but if it can be proved that your employer deliberately placed you in harm's way, other legal actions can be taken to gain additional compensation to provide for your medical and future needs.

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Gases and vapors continue to pose hazards on oil and gas well sites during gauging, fluid transfer, and disposal

Posted on by Kyla Retzer, MPH; Emily Schmick, MSPH, CIH; Alejandra Ramirez-Cardenas, MPH; Bradley King, PhD, MPH, CIH; and John Snawder, PhD, DABT

Background

1) The worker peers down an open hatch of the oil tank. 2) In some regions, workers gauge oil tanks by opening tank hatches, visually observing liquid levels, and then manually measuring liquid oil levels. 3) As commonly designed, fixed oil tanks often are interconnected for both liquid and vapor, allowing contents to equalize over multiple tanks. Equalization of tanks can result in a high volume of off-gassed vapors when a tank hatch is opened. 4) The windsock is a visual indicator for the worker to stay positioned upwind while gauging. Photo courtesy of OSHA
A previous NIOSH report (2016)1 described the death of nine oil and gas extraction workers that occurred during gauging or sampling activities at open thief hatches on crude oil storage tanks. Hydrocarbon gases and vapors (HGVs) and associated oxygen displacement were the primary or contributory factors in these fatalities. Additionally, wellsite exposure assessments conducted by OSHA and NIOSH identified HGVs at open thief hatches in concentrations that were immediately dangerous to life or health (IDLH) and in excess of the lower explosive limit (LEL), creating a chance for fires and explosions. It has been demonstrated that HGVs can build up under pressure and rapidly escape when thief hatches of production, flowback, and other tanks are opened, creating a highly flammable and oxygen-deficient environment, even in areas not considered to be a confined space. Acute exposure to HGVs can have narcotic effects on workers (i.e. dizziness, disorientation) as well as affect the eyes, lungs, and central nervous system. The simultaneous exposure of HGVs combined with a low oxygen atmosphere may also pose a risk for sudden cardiac death, especially in individuals with pre-existing coronary artery disease. In addition to HGVs, hydrogen sulfide (H2S), a widely recognized hazard in the oil and gas extraction industry, continues to persist as a cause of death among workers2. Hydrogen sulfide is naturally present in some oil and gas deposits and may be produced as a by-product of the desulfurization process of these fuels. Workers in all operations during oil and natural gas exploration and production may be exposed to H2S. This blog provides an update on fatalities, injuries, and exposures associated with hazardous gases and vapors (HGVs and H2S) in the oil and gas extraction industry, and alerts employers to exposures that can occur while working around oil and gas process fluids.

What’s New?

NIOSH has conducted surveillance of worker fatalities and severe injuries in the oil and gas extraction industry, including those that may be associated with exposure to or ignition of hazardous gases and vapors. Fatalities are identified using the NIOSH Fatalities in Oil and Gas Database (FOG). The federal Occupational Safety and Health Administration (OSHA) severe injury data set provides a source to identify severe non-fatal incidents among oil and gas extraction workers. In addition to fatality and injury surveillance, NIOSH has conducted additional worker exposure assessments at oil and gas worksites to examine potential hazardous exposures, including oxygen concentration and hazardous and flammable gas and vapor concentrations (HGVs and H2S) during various worker activities.

Surveillance

NIOSH researchers sought to determine the number of fatalities and hospitalizations with known or potential exposure to hazardous gases and vapors as well as fires and explosions while working around process fluids, including waste water, flowback, petroleum condensate, or crude oil. Waste water is also sometimes referred to as produced water, brine, salt water, etc., but often still contain hydrocarbons.
The following definition was developed to identify cases: During 2015-2016, fatalities or hospitalizations related to the ignition, inhalation, or suspected inhalation of HGVs and/or H2S while handling process fluids (e.g. fluid transfer) or working on tanks containing process fluids at oil and gas well sites or waste water disposal sites. Cases were reviewed and categorized by event type, activity type, location, and fluid type.
During 2015—2016, there were eight oil and gas worker fatalities during eight separate incidents that met the case definition (see cases in FOG Report ).
  • Event Type: Three workers died of sudden cardiac death with potential exposures to hazardous gases and vapors, two workers died due to fire/explosions, two workers died due to hydrogen sulfide poisoning, and one worker died due to HGV exposures.
  • Activity Type: Four workers died while transferring fluids from tanks to trucks, two workers were tank gauging or sampling, one worker was at an open tank hatch with unknown activity, and one worker was doing hotwork (grinding) on top of a tank.
  • Fluid Type: Four workers were working with produced water, three workers were working with crude oil, and one with flowback.
  • Site Type: Six workers died at well sites and two workers died at waste water disposal sites.
During 2015-2016, there were ten hospitalizations during ten separate incidents that met the case definition (see cases in FOG Report).
  • Event Type: Five workers were hospitalized due to fire/explosions, three workers hospitalized due to H2S exposure, and two workers hospitalized due to HGV exposures.
  • Activity Type: Six workers were tank gauging or sampling, one worker was transferring fluids, one worker was using a vacuum truck to remove tank bottoms, one worker was draining condensate from a separator line (i.e. heater treater), and one was transporting waste water.
  • Fluid Type: Three workers were working with produced water, one with flowback, one with tank bottoms (solids and waste), one with condensate, one with crude oil, and three were unknown.
  • Site Type: Nine workers were injured/exposed at well sites and one worker was injured at a waste water disposal site.
These incidents illustrate that hazardous gas and vapor exposures while handling process fluids continue to occur, either through the inhalation or ignition of hazardous gases and vapors.

Exposure assessments

In July 2017, NIOSH conducted air monitoring while a trucker was transferring petroleum condensate from a storage tank onto his truck. As hydrocarbon fluids were transferred, gases and vapors that were previously in equilibrium within the storage tank released into the belly of the truck’s tank. To prevent over pressuring of the truck tank as liquid was transferred, the gases and vapors were vented directly to the outside of the back of the truck; no vent line was used to direct the gases and vapors away from the trunk at a distance. Direct reading instrument data and bulk air samples were collected at and around the tanker trunk and later analyzed to determine HGV and H2S concentrations in the air during this activity. Forward-looking Infrared (FLIR) video was used to visualize and record the plume of hazardous gases and vapors that surrounds the tanker truck during the fluid transfer (click for video).
While performing this fluid transfer, hazardous gases and vapors were measured in concentrations over 348,000 parts per million, or 34.8% of the air volume. The full analysis of this air sample is shown in Table 1.
Table 1. Results for select gases and vapors collected during petroleum condensate transfer near the venting point behind the tanker truck

Gas/Vapor Concentration (ppm) IDLH (ppm) Severity (Concentration/IDLH)
Methane** 141,000 5,000* 28
Ethane** 62,600 3,000* 21
Propane** 59,100 2,100* 28
Butanes** 50,900 1,600* 31
Pentanes** 25,500 1,500* 17
Benzene† 175 500 0.35
Toluene† 6.8 500 0.01
Ethylbenzene† Not Detected 800* 0.0
Xylenes† 0.5 900 0.0
Hexane† 6,000 1,100* 5.5
Heptane† 3,510 750 4.7
Octane† Not Detected 1,000* 0.0
Nonane† 0.8 800* 0.0
Hydrogen Sulfide‡ 450 100 4.5
* Immediately Dangerous to Life or Health (IDLH) values are based on the NIOSH Current Intelligence Bulletin 663, which states “In the event that the derived health-based IDLH value exceeds 10% of the LEL concentration for a flammable gas or vapor, the air concentration that is equal to 10% of the LEL will become the default IDLH value for the chemical.”
** Analysis Method- Gas chromatography-flame ionization detector (GC-FID)
† Analysis Method- Gas chromatography-photoionization detector (GC-PID)
‡ Analysis Method- Direct reading instrument with electrochemical sensor

Recommendations for Employers, Workers, and Incident Investigators

Oil and gas worker fatalities and hospitalizations due to ignition or inhalation of hazardous gases and vapors and associated oxygen deficiency are preventable. There are a number of resources available that employers and workers can use to prevent these incidents.

Employers

Implement recommendations contained in the following relevant resources to prevent exposures to hazardous gases and vapors:

Workers

Comply with all employer policies and hazard assessments to ensure you are protected from hazardous gases and vapors. Always wear required personal protective equipment and your multi-gas monitor and heed all alarms. Review the videos listed above and each of the National STEPS Network Hazard Alerts to learn more ways to protect yourself.

Incident investigators

Medical examiners and coroners investigating oil and gas worker fatalities need to be aware of the possibility of hazardous gas and vapor exposures and request appropriate lab tests. Exposure to high concentrations of HGVs and oxygen-deficient atmospheres can result in sudden cardiac death in oil and gas extraction workers. Analysis of ante-mortem or postmortem blood for documentation of HGV exposure (2139B) as well as H2S (thiosulfate in blood) is available from clinical toxicology laboratories.

Help Wanted!

NIOSH is working with industry partners to continue to evaluate the magnitude of hazards and effectiveness of controls in the oil and gas industry. We are looking for industry partners who are interested in participating in studies and/or providing access to sites to assess exposures. If you have questions, or would like to provide pertinent information on this topic, please contact us via the blog comment box or by email at kretzer@cdc.gov.
Kyla D. Retzer, MPH, is an Epidemiologist in the NIOSH Western States Division. 
Emily Schmick, MSPH, CIH, is an ORISE Research Fellow in the NIOSH Western States Division.
Alejandra Ramirez-Cardenas, MPH, is a Research Assistant in the NIOSH Western States Division.
John Snawder, PhD, DABT, is a Research Toxicologist in the NIOSH Division of Applied Research and Toxicology.
Bradley King, PhD, MPH, CIH, is an Industrial Hygienist in the NIOSH Western States Division.

Note:  The objective of this blog entry is to describe a potential emerging occupational hazard in the oil and gas extraction industry. Additionally, it is meant to request help from stakeholders for more information related to illnesses, injuries, and fatalities associated with fluid transfer. To keep the blog discussion focused on worker health, we may choose not to respond to comments that do not pertain to worker exposures.

Acknowledgements

Ted Teske, Ryan Hill, Robert Harrison (California Department of Public Health), Michael Hodgson (OSHA), J.D. Danni (OSHA), Mike Marshall (OSHA), Barbara Alexander

References

Esswein EJ, Retzer K, King B, Cook-Shimanek M. Environmental and Health Issues in Unconventional Oil and Gas Development. Kaden DA, Rose TL, eds. Waltham MA: Elsevier, 2016 Jan: 93-105.
Harrison RJ, Retzer K, Kosnett MJ, et al. Sudden Deaths Among Oil and Gas Extraction Workers Resulting from Oxygen Deficiency and Inhalation of Hydrocarbon Gases and Vapors — United States, January 2010–March 2015. MMWR Morb Mortal Wkly Rep 2016;65:6–9. DOI: http://dx.doi.org/10.15585/mmwr.mm6501a2
NIOSH [2013]. Current intelligence bulletin 66: derivation of immediately dangerous to life or health (IDLH) values. Cincinnati, OH: US Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication 2014–100. https://www.cdc.gov/niosh/docs/2014-100/pdfs/2014-100.pdf


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Sudden Deaths Among Oil and Gas Extraction Workers Resulting from Oxygen Deficiency and Inhalation of Hydrocarbon Gases and Vapors — United States, January 2010–March 2015

Weekly / January 15, 2016 / 65(1);6–9

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Robert J. Harrison, MD1; Kyla Retzer, MPH2; Michael J. Kosnett, MD3,4; Michael Hodgson, MD5; Todd Jordan, MSPH6; Sophia Ridl2; Max Kiefer, MS2 (View author affiliations)
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Summary

What is already known on this topic?
Oil and gas extraction workers experience high rates of traumatic work-related fatalities. Tank gauging and sampling activities can expose workers to high concentrations of hydrocarbon gases and vapors (HGVs), in some cases at levels immediately dangerous to life or health.
What is added by this report?
Exposure to high concentrations of HGVs and oxygen-deficient atmospheres during manual tank gauging and sampling can pose a risk for sudden cardiac death. Although the first two deaths described in this series were not immediately recognized as work-related, the occurrence of seven additional deaths under similar circumstances suggests that HGV exposure during manual tank gauging and sampling can be life-threatening.
What are the implications for public health practice?
Health care professionals need to be aware of the risks to oil and gas extraction workers related to exposure to high concentrations of HGVs and to oxygen deficiency. Medical examiners and coroners investigating worksite fatalities need to be aware that these exposures can result in sudden cardiac death and include appropriate toxicology analyses in their investigation. A thorough worksite assessment is warranted if any workers exhibit signs or symptoms of HGV exposure or oxygen deficiency. Implementation of measures to reduce or eliminate HGV exposures is important, including practices that allow for alternative fluid sample collection points, remote monitoring of fluid levels, proper use of gas monitors, respiratory protection meeting the requirements of the Occupational Safety and Health Administration, and worker training.
In 2013, an occupational medicine physician from the University of California, San Francisco, contacted CDC’s National Institute for Occupational Safety and Health (NIOSH), and the Occupational Safety and Health Administration (OSHA) about two oil and gas extraction worker deaths in the western United States. The suspected cause of these deaths was exposure to hydrocarbon gases and vapors (HGVs) and oxygen (O2)-deficient atmospheres after opening the hatches of hydrocarbon storage tanks. The physician and experts from NIOSH and OSHA reviewed available fatality reports from January 2010 to March 2015, and identified seven additional deaths with similar characteristics (nine total deaths). Recommendations were made to industry and regulators regarding the hazards associated with opening hatches of tanks, and controls to reduce or eliminate the potential for HGV exposure were proposed. Health care professionals who treat or evaluate oil and gas workers need to be aware that workers might report symptoms of exposure to high concentrations of HGVs and possible O2 deficiency; employers and workers need to be aware of this hazard and know how to limit exposure. Medical examiners investigating the death of oil and gas workers who open tank hatches should consider the contribution of O2 deficiency and HGV exposure.
Workers at oil and gas well sites often manually gauge the level of fluid or collect a sample from storage tanks containing process fluids. These workers climb to the top of the tanks, open a “thief” hatch (a closable aperture on atmospheric tanks, used to sample the tank contents) (Figure), and either place a device into the hatch to measure the fluid level or lower a “thief” sampler (a hollow tube) into the tank to collect liquid samples. In 2013, an occupational medicine physician from the University of California, San Francisco, received a report of a 2012 oil and gas worker fatality in North Dakota; that state’s medical examiner attributed death to the inhalation of petroleum hydrocarbons. The male worker, aged 21 years, was gauging crude oil production tanks on the well site, at night and alone. A coworker found the victim unconscious near the open hatch. Colleagues initiated cardiopulmonary resuscitation, and the worker was transported to the hospital where he was pronounced dead approximately 2 hours later. An autopsy found no obvious signs of traumatic injury. Toxicology testing identified detectable quantities of low–molecular weight hydrocarbons (propane and butane), and evidence of heavier molecular weight hydrocarbons. No indication of exposure to hydrogen sulfide (H2S) was identified. Initially, the death was attributed to cardiovascular disease and later to hydrocarbons. The occupational medicine physician subsequently identified a second worker who died from a sudden cardiac event in 2010 while performing tank gauging; H2S was excluded as a factor. The physician contacted NIOSH and OSHA about these two deaths.
To identify other oil and gas extraction worker fatalities associated with exposure to HGVs, the physician and experts from NIOSH and OSHA reviewed media reports, OSHA case files, and the NIOSH Fatalities in Oil and Gas database. Cases were defined as nontraumatic oil and gas extraction worker deaths occurring during January 2010–March 2015, in which the workers were 1) performing tank gauging, sampling, or fluid transfer activities at oil and gas well sites; 2) working in proximity to a known and concentrated source of HGVs (e.g., an open hatch); 3) not working in a confined space; and 4) not exposed to H2S, fires, or explosions. All available information on identified fatalities was reviewed, including OSHA investigations, coroner and toxicology reports, gas monitor data, and exposure assessment data.
Nine deaths, occurring from January 2010 to March 2105, were identified (Table); six of the deaths occurred during 2014. Three deaths occurred in Colorado, three in North Dakota, and one each in Montana, Oklahoma, and Texas. The median age of workers was 51 years (range = 20–63 years), and all were male. All of the victims were working alone at the time of the incidents and were found collapsed on a tank or catwalk, or at the base of the catwalk stairs. In at least five cases, the hatch was open when the worker was found. Five of the fatalities occurred during the collection of a fluid sample, and four occurred during tank gauging. Toxicologic data on HGVs were not consistently collected during autopsy, but petroleum hydrocarbon vapors were noted as a cause of death for three workers.
Only one of the nine workers was known to have been provided a respirator, but fit-testing had not occurred, and the air-purifying respirator was not suitable for high concentrations of HGVs or O2 deficiency. The exposure assessment conducted by OSHA following the 2010 case found O2 concentrations as low as 11% at 1 foot above the open thief hatch (O2 concentrations in ambient air = 21%). In addition, HGV concentrations were in excess of the lower-explosive limit (minimum concentration of a gas necessary to support its combustion in air), suggesting exposures high enough (>10,000 parts per million [ppm]) to cause acute central nervous system symptoms. In case number seven, the worker wore a data-logging, continuous multi gas monitor as a regular work practice. Three weeks before the fatal event, he was examined in an emergency department after experiencing altered consciousness while gauging a tank. Gas monitor data during this event revealed a 5-minute interval, concurrent with his symptoms, when O2 concentrations were in the range of 10% to 15% and flammable HGVs exceeded the lower-explosive limit. On the day of his death, the gas monitor again indicated that the lower-explosive limit had been exceeded, with O2 concentrations as low as 7%.
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Discussion

During January 2010–March 2015, at least nine deaths of oil and gas workers occurred in the United States, with exposure to HGVs a confirmed or suspected factor. Oil and gas extraction is a high-risk industry, with overall occupational fatality rates seven times the national average (1). Although safety hazards in the industry are well-known, few published reports address chemical exposures and acute occupational illness associated with oil and gas extraction. Recent exposure assessments have identified that opening thief hatches and manual gauging or sampling from hydrocarbon-containing tanks, outdoors in nonconfined spaces, is widely practiced and poses substantial and potentially lethal hazards to workers (2–4). These hazards include sudden exposure to high concentrations (>100,000 ppm) of low–molecular weight HGVs, accompanied by displacement of air, resulting in O2 deficiency. Inhaled O2 concentrations of <15% can significantly impair central nervous system function, and concentrations of <10% can result in loss of consciousness and possible death within seconds to minutes (5). Low O2 blood levels (hypoxemia) can exacerbate cardiac ischemia and increase the release of epinephrine (adrenalin). High concentrations (i.e., 50,000 ppm to ≥100,000 ppm) of low–molecular weight hydrocarbons, particularly butane, have been shown in animal studies and human reports to sensitize the heart to epinephrine-induced ventricular fibrillation, a lethal cardiac arrhythmia (6–8). The simultaneous exposure to high levels of low–molecular weight HGVs and a low O2 atmosphere above an open tank hatch poses a risk for sudden cardiac death. Preexisting coronary artery disease can exacerbate that risk. In addition, high levels of low–molecular weight HGVs can exert anesthetic effects that contribute to central nervous system depression (9). The exposure-assessment samples also showed concentrations of propane, butane, pentane, and 2-methylbutane exceeding 100% of the lower-explosive limit (3). Concentrations of explosive gases in excess of 10% of the lower-explosive limit are considered immediately dangerous to life or health. Because of the nine identified fatalities, the exposure-assessment findings, and the potential mechanism for sudden cardiac death, OSHA, NIOSH and multiple industry stakeholders collaboratively issued a hazard alert on tank gauging at oil and gas well sites (10). In addition, the Bureau of Land Management has proposed changes to current federal regulations* that replace outdated technology and practices with remote tank gauging technologies, reducing or eliminating the need for manual tank gauging.
Health professionals need to recognize the signs and symptoms of exposure to high concentrations of HGVs and possible O2-deficient atmospheres in oil and gas workers. Health and safety professionals need to recognize and act on nonfatal warning signs and symptoms, such as dizziness, confusion, immobility, and collapse in oil and gas workers who might have been exposed to high concentrations of HGVs and to O2-deficient atmospheres. As required by OSHA regulations, employers should reduce or eliminate the hazard; this can include practices that allow for alternative fluid sample collection points, remote monitoring of fluid levels, proper use of gas monitors, respiratory protection meeting OSHA requirements, and worker training. Employers also need to ensure that workers do not work alone where they might have risks for exposures to high concentrations of hydrocarbons and low-O2 environments. Having automated external defibrillators available at worksites is also important. Medical examiners and coroners investigating workplace fatalities need to be aware of the possibility that exposure to high concentrations of HGVs and O2-deficient atmospheres can result in sudden cardiac death in oil and gas extraction workers. Analysis of antemortem or postmortem blood for documentation of HGV exposure is available from clinical toxicology laboratories.
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Acknowledgments

Maggie Cook-Shimanek, Eric Esswein, Ryan Hill, Bradley King, John Snawder, Ann Krake.
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Corresponding author: Robert J. Harrison, Robert.harrison@ucsf.edu, 415-885-7580.
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1Division of Occupational and Environmental Medicine, University of California, San Francisco; 2National Institute for Occupational Safety and Health, Western States Division, CDC; 3Division of Clinical Pharmacology and Toxicology, University of Colorado School of Medicine; 4Department of Environmental and Occupational Health, Colorado School of Public Health; 5Office of Occupational Medicine and Nursing, Occupational Safety and Health Administration, Washington, DC; 6Health Response Team, Occupational Safety and Health Administration, Salt Lake City, Utah.
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References

  1. Mason KL, Retzer KD, Hill R, Lincoln JM. Occupational fatalities during the oil and gas boom—United States, 2003–2013. MMWR Morb Mortal Wkly Rep 2015;64:551–4. PubMed
  2. Esswein EJ, Snawder J, King B, Breitenstein M, Alexander-Scott M, Kiefer M. Evaluation of some potential chemical exposure risks during flowback operations in unconventional oil and gas extraction: preliminary results. J Occup Environ Hyg 2014;11:D174–84. CrossRef PubMed
  3. Jordan T. Hydrocarbon exposures during tank gauging and sampling operations [presentation]. NIOSH National Occupational Research Agenda Oil and Gas Sector Council Meeting, March 19, 2015. http://www.nationalstepsnetwork.com/docs_tank_gauging/NORA_Oil_and_Gas_Council_Meeting_March2015.pdf.
  4. King B, Esswein E, Retzer K, et al. UPDATE: reports of worker fatalities during manual tank gauging and sampling in the oil and gas extraction industry. In: NIOSH Science Blog. Washington DC: National Institute for Occupational Safety and Health. http://blogs.cdc.gov/niosh-science-blog/2015/04/10/flowback-3/.
  5. Miller TM, Mazur PO. Oxygen deficiency hazards associated with liquefied gas systems: derivation of a program of controls. Am Ind Hyg Assoc J 1984;45:293–8. CrossRef PubMed
  6. Chenoweth MB. Ventricular fibrillation induced by hydrocarbons and epinephrine. J Ind Hyg Toxicol 1946;28:151–8. PubMed
  7. Reinhardt CF, Azar A, Maxfield ME, Smith PE Jr, Mullin LS. Cardiac arrhythmias and aerosol “sniffing”. Arch Environ Health 1971;22:265–79. CrossRef PubMed
  8. Fuke C, Miyazaki T, Arao T, et al. A fatal case considered to be due to cardiac arrhythmia associated with butane inhalation. Leg Med (Tokyo) 2002;4:134–8. CrossRef PubMed
  9. Drummond I. Light hydrocarbon gases: a narcotic, asphyxiant, or flammable hazard? Appl Occup Environ Hyg 1993;8:120–5. CrossRef
  10. Occupational Health and Safety Administration National Steps Alliance. Tank hazard alert: gauging, thieving, fluid handling. How to recognize and avoid hazards [poster]. Washington, DC: U.S. Department of Labor, Occupational Health and Safety Administration; 2015. http://www.nationalstepsnetwork.org/docs_tank_gauging/TankHazardInfographicFinal04_22_15.pdf.
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Return to your place in the textFIGURE. An oil field worker manually gauges the level of process fluid in a fixed production oil tank* — United States
The figure above is a photograph showing an oil field worker manually gauging the level of process fluid in a fixed production oil tank.Photo/Todd Jordan, Occupational Safety and Health Administration
*1) The worker peers down an open hatch of the oil tank. 2) In some regions, workers gauge oil tanks by opening tank hatches, visually observing liquid levels, and then manually measuring liquid oil levels. 3) As commonly designed, fixed oil tanks often are interconnected for both liquid and vapor, allowing contents to equalize over multiple tanks. Equalization of tanks can result in a high volume of off-gassed vapors when a tank hatch is opened. 4) The windsock is a visual indicator for the worker to stay positioned upwind while gauging.
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Return to your place in the textTABLE. Sudden deaths caused by inhalation of hydrocarbon gases and vapors and oxygen deficiency among oil and gas extraction workers — United States, January 2010–March 2015
Worker Year of death Age (yrs) State Job title Job task Location/position of decedent when found Time of day found Coroner’s stated cause of death
1 2010 30 Montana Crew worker Gauging Slumped over on catwalk 3:00 a.m. Hypertensive and atherosclerotic cardiovascular disease
2 2012 21 North Dakota Flow tester Gauging On catwalk next to open hatch 12:30 a.m. Hydrocarbon poisoning due to inhalation of petroleum vapors
3 2013 39 North Dakota Truck driver Collecting sample On knees, slumped over catwalk railing in front of open hatch 10:20 a.m. Sudden cardiac arrhythmia (primary), morbid obesity and arteriosclerotic heart disease (contributory)
4 2014 57 Oklahoma Truck driver Collecting sample Slumped over on catwalk next to tank 10:12 a.m. (time of death) Undetermined (no autopsy performed)
5 2014 51 Colorado Truck driver Collecting sample Hanging from guardrail, hooked by clothing 10:39 a.m. (time of death) Sudden cardiac death due to ischemic heart disease
6 2014 57 Colorado Truck driver Collecting sample Collapsed over open hatch 10:30 a.m. Atherosclerotic cardiovascular disease
7 2014 59 Colorado Truck driver Collecting sample Collapsed over open hatch 1:40 p.m. Toxic gas inhalation and oxygen displacement by volatile hydrocarbons (primary), atherosclerotic cardiovascular disease
8 2014 63 Texas Tank gauger Gauging At bottom of catwalk stairs 4:14 a.m. Arteriosclerotic and hypertensive cardiovascular disease
9 2014 20 North Dakota Flow tester Gauging Face down over open hatch 5:00 a.m. Cardiac arrhythmia, with cardiac hypertrophy, coronary artery hypogenesis, obesity and petroleum hydrocarbon vapors
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Suggested citation for this article: Harrison RJ, Retzer K, Kosnett MJ, et al. Sudden Deaths Among Oil and Gas Extraction Workers Resulting from Oxygen Deficiency and Inhalation of Hydrocarbon Gases and Vapors — United States, January 2010–March 2015. MMWR Morb Mortal Wkly Rep 2016;65:6–9. DOI: http://dx.doi.org/10.15585/mmwr.mm6501a2.
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