OHS Canada Magazine

Toxic Fissures

Avatar photo

December 2, 2014
By Jean Lian

Environment/Climate Change Health & Safety Hydraulic fracturing occupational exposure Oil and gas

What goes down must come up. Flowback fluids — returning high-pressure fluids injected into the ground to fracture the rock formation and release natural gas or oil — have been linked to the deaths of four workers who appear to have suffered from acute chemical exposures during flowback operations at well sites in Williston Basin in North Dakota and Montana since 2010. As Canada’s oil-and-gas boom continues to fuel projects that involve hydraulic fracturing, just how much — or how little — do we know about what goes on underground?

The fatalities came to the attention of the Washington, D.C.-based National Institute for Occupational Safety and Health (NIOSH) via media reports, officials with the United States’ Occupational Safety and Health Administration and members of the academic community. Christina Spring, spokesperson for NIOSH’s parent agency, the Centers for Disease Control and Prevention, says NIOSH is still working to obtain additional information about these and other fatalities. As such, it cannot make any “definitive statements” about the relationship between these fatalities and acute chemical exposures that may be associated with gauging tanks during flowback and production-testing operations.

According to NIOSH, fracking fluids present an exposure hazard to only a few workers involved in the handling and mixing of the fluids, which are typically transferred from bulk containers into closed systems by workers wearing personal protective equipment.

“We have conducted some limited worker-exposure assessments to hydraulic-fracturing fluid components,” Spring reports. “Our data did not find any exposures to the chemicals used in the hydraulic fracturing that exceeded NIOSH-recommended exposure limits.”

But this is where the contention begins. “The problem is that it is such a wide variety of chemicals they use,” Dr. Frank Atherton, deputy chief medical officer of health with the Government of Nova Scotia in Halifax, says about fracking fluids, which are a cocktail of various chemicals — many of which are pretty benign like guar gum, a food-grade, water-soluble paste made from the seeds of the guar plant and used as a thickener and stabilizer in foods like jelly. “So there is really nothing specific around fracking fluids that you can point to and say, ‘This is a specifically toxic chemical.’”

William Stringfellow, Ph.D., director of the Ecological Engineering Research Program at the University of the Pacific in Stockton, California, says the chemical list is fairly extensive. “There are about 250 compounds so far that we have identified as being used in fracturing in one way or another.”


In a paper published online in the Journal of Hazardous Materials in April, Dr. Stringfellow’s team at Lawrence Berkeley National Laboratory and the University of the Pacific compiled a list of substances commonly used in fracking and found that these fluids do indeed contain many non-toxic, food-grade materials. But the researchers also identified eight compounds, including biocides, that were particularly toxic to mammals.

“There are a number of chemicals, like corrosion inhibitors and biocides, in particular, that are being used in reasonably high concentrations that potentially could have adverse effects,” Dr. Stringfellow says. “Biocides, for example, are designed to kill bacteria — it is not a benign material.”

A Primer
Much of the controversy surrounding fracking activities stems from relatively recent technological breakthroughs. According to a report that addresses the environmental and associated health impacts of shale-gas extraction in Canada, released in May by the Council of Canadian Academies (CCA), shale-gas production through natural fractures that allow shallow vertical wells to produce at low rates over a long time has been around for decades.

But in the last 20 years, large-scale commercial production of much deeper shale-gas reservoirs has become possible since the Texas Barnett Shale pioneered a new drilling technique that combines two different technologies — horizontal drilling and multi-stage hydraulic fracturing. This process involves drilling the gas well vertically from the surface before bending it at a certain depth to penetrate the shale-gas layer horizontally or diagonally.

The combination of these two technologies presents new environmental and health and safety issues: using greater amounts of water, sand and chemicals; requiring higher injection rates to fracture a much larger volume of rock; and applying this method to a broader spectrum of unconventional oil and gas resources. In North America, more than 150,000 horizontal wells have been completed using multi-stage hydraulic fracturing in recent years, of which only one-quarter are shale-gas wells, the CCA report notes.

According to the Primer on the Process of Hydraulic Fracturing — drafted by the expert panel of Nova Scotia’s Hydraulic Fracturing Independent Review and Public Consultation, of which Dr. Atherton is one of the expert panelists — fracking fluids typically consist of water, proppants (like sand and ceramic pellets to hold the fracture open, so that natural gas can be extracted) and chemical additives.

About 98 per cent of the volume of fracking fluid is composed of water; the remaining one to two per cent is made up of proppants and chemical additives, which can include acid (to reduce fracture initiation pressure and clean up excess cement), scale inhibitor (to prevent scale build-up on the walls of the well and eliminate the potential for blockage of tubing and equipment), biocides (to control the growth of microbes that will hinder the flow of gas), surfactants (to reduce the viscosity of the fracking fluid), gelation chemicals (to act as thickeners to initiate the fractures and carry some of the sand), friction reducers and corrosion inhibitors.

While many of these chemicals may be used in fairly small concentrations, they are not necessarily stored at low concentrations. “So from a worker point of view, they may be a very dilute acid when it gets used, but there is a tank of acid there or barrels of acid that need to be handled carefully, and you need to follow the proper safety protocols when you are handling those materials,” Dr. Stringfellow says. “You need to look at not just the concentration, but the total mass material that is being used on the site, and make evaluations based on how hazardous the material is and volumes of the material used.”

For instance, one per cent of a 50,000 cubic metre (m³) hydraulic-fracture stimulation would require 500 m³ of chemical additives. If 10 wells on the same well pad all undergo the same treatment, that would translate into 5,000 m³ of chemical additives. As a result, fracking may introduce new exposure risks through an added suite of chemicals and physical agents on the worksite. An increasingly recognized health risk to workers is the inhalation of silica used as a proppant in fracking, which can cause silicosis, lung cancer and other diseases, the CCA report notes.

Once the injection process is complete, the internal pressure of the rock formation causes flowback water to return to the surface through the well bore. It is estimated that 25 to 75 per cent of the injected fluid will flow back to the surface over the producing lifetime of the well. Factors that determine the volume of flowback water include the properties of the unconventional gas, the design of the fracturing program and the type of fracking fluid used, the Nova Scotia primer notes.

Apart from the injected water, proppant and chemicals, flowback water may contain some endogenous materials, including natural gas, salty brines, metals, nutrients, naturally occurring radioactive materials (NORM) and other organic compounds. Workers can also be exposed to NORMs that accumulate on equipment and machinery through skin contact, in addition to inhalation and water exposure.

Noxious Receptacles
As flowback fluids are often stored in tanks or open-pit ponds onsite, potential exposure to fracking fluids can occur during storage and waste disposal. One of the major exposure problems associated with tankage is the opening up of tanks.

“During tankage, people need to be very careful about opening tanks, standing over tanks,” Dr. Stringfellow cautions, citing chemical reactions that can give rise to oxygen-deficient or noxious gases like hydrogen sulphide.

To determine the volume of liquids in flowback and production tanks, workers must periodically gauge fluid levels using a hand-held gauging stick or hand-cranked gauging tape for deeper production tanks. Other task-based activities during flowback include the following: setting and changing chokes to manage fluid flows; checking valves and determining the volume, flow rate and accumulation of process fluids; maintaining piping; and monitoring and maintaining oil, gas and water separators.

As these tasks require workers to access the tanks through hatches located on the top, the fluids in each tank can create a confined space in which hydrocarbons accumulate and lead to exposures for workers gauging fluids, says Lalita Bharadwaj, Ph.D., associate professor with the School of Public Health at the University of Saskatchewan in Saskatoon.

“Depending on the volume of the fluid within that pond, there could be some physical hazard to the worker if they are in the vicinity of the large leakage or break, for example, as a result of the fluid rushing out of the pond,” she cautions.

To understand the risks of chemical exposures in modern oil-and-gas extraction operations, NIOSH published in August the preliminary results of its evaluation of some potential chemical-exposure risks during flowback operations at six unconventional oil-and-gas extraction sites in Colorado and Wyoming during the spring and summer of 2013. Exposure assessments conducted during normal, 12-hour operations identified benzene, which is present naturally in flowback fluids, as the primary volatile-organic-compound (VOC) hazard for workers, not only because of its carcinogenicity; it is also acutely toxic to the nervous system, liver and kidneys at high concentrations. Inhalation risks for benzene exposures appear to be associated with the amount of time spent working in close proximity to hydrocarbon sources, such as around hatches on flowback and production tanks.

Fifteen of the 17 samples analyzed met or exceeded the NIOSH-recommended exposure limit of 0.1 parts per million (ppm) as a full-shift total weighted average (TWA), and two of the 17 samples met or exceeded the American Conference of Governmental Industrial Hygienists’ threshold limit value of 0.5 ppm as a full-shift TWA for benzene. Respirable silica was also detected in four of five personal-breathing-zone samples.

Opening thief hatches and gauging tanks are the primary task-based activities that increase inhalation exposure risks. Additional exposures may occur due to fugitive emissions from equipment in other areas in the flowback process, such as chokes, separators, piping and valves, particularly when one performs maintenance on these items, the NIOSH report concludes. Although workers at all locations wore personal protective equipment, none of the flowback technicians, production-watch technicians or water-management technicians donned respirators, nor were they clean-shaven, which would have been necessary if respirators had been used.

Potential chemical exposures may also occur during many stages of exploration and production, which can give rise to VOCs, including naphthalene, toluene, ethylbenzene and xylene. Other VOCs associated with hydraulic fracturing and flowback — for example, propargyl alcohol, methanol and dimethylformamide — have the potential to injure multiple organ systems when exposures exceeding occupational exposure limits are repeated and not well controlled.

As airborne concentrations of hydrocarbons and benzene fluctuate greatly during flowback operations, depending on the temperature and pressure of the process liquids and reservoir hydrocarbon conditions, “the unpredictability of exposure risks warrants conservative approaches to protecting workers,” the NIOSH report recommends.

Dr. Bharadwaj thinks that there should be alternative work processes to replace those in which exposure risks are inherent. “Currently, the gauging operations to determine fluid levels in tanks are done manually. Perhaps there could be development of automated gauging operations that could take the place of those manual operations,” she suggests.

Meanwhile, the NIOSH report recommends the following measures for companies that conduct flowback operations:

•   Develop alternative tank-gauging procedures to limit exposures to hydrocarbon vapours emitted from hatches on the top of tanks. Adapt flowback and production tank-sampling ports with vents that exhaust away from workers or eliminate the use of hatches as primary access points;

•   Provide training to ensure that flowback technicians understand the hazards of exposure to benzene and other hydrocarbons, the importance of monitoring atmospheric conditions for lower explosive limit concentrations and how to apply work practices that limit their exposures to chemicals and the potential for fires and explosions;

•   Limit the time personnel spend in proximity to hydrocarbon sources, establish a controlled perimeter around flowback tanks and require that any portable tents or sunshades remain out of and upwind of the controlled area;

•   Use calibrated personal flammable-gas monitors with alarms in areas near flowback tanks;

•   Use respiratory protection as an interim measure until engineering and administrative controls are implemented;

•   Use proper hand protection to prevent dermal exposure to liquid hydrocarbons; and

•   Monitor workers to determine risks for benzene exposures through personal breathing zones and real-time air sampling for activities involving exposure to flowback fluids.

Deadly Secrets
What you do not know cannot hurt you. But when it comes to fracking fluids, that adage cannot be further from the truth.

British Columbia became the first province in Canada to enforce the public disclosure of ingredients used for hydraulic fracturing on January 1, 2012. The law requires companies to upload a list of ingredients used in fracking to FracFocus within 30 days of completing operations — the point in time when a well is able to produce gas. The site collects voluntary submissions of chemicals used by fracking companies.

Alberta followed in British Columbia’s footsteps later that same year. In November 2013, the National Energy Board (NEB) jumped on the bandwagon after signing an agreement with the British Columbia Oil and Gas Commission, the Ground Water Protection Council and the Interstate Oil and Gas Compact Commission to participate in the FracFocus.ca website. On October 30, 2013, the NEB issued the first and only authorization for multi-stage hydraulic fracturing in horizontal wells in the north. Those two wells were drilled last winter, and ConocoPhillips disclosed the chemicals used on the FracFocus.ca website, NEB spokesperson Tara O’Donovan says from Calgary.

While Canada is moving towards greater transparency regarding the disclosure of substances used in fracking, some chemicals remain shrouded in secrecy. Although reporting to the National Pollutant Release Inventory (NPRI) — Canada’s legislated, publicly-accessible inventory of pollutant releases to air, water and land, including disposals and transfers for recycling — is mandatory for operators of facilities that meet NPRI-reporting requirements, hydraulic-fracturing activities are exempt from reporting to the NPRI. Facilities that conduct well-drilling and completion activities, including fracking, do not generally meet the NPRI’s employee threshold, information from Environment Canada notes.

As well, while the additives used in fracturing fluids are generically similar, each company uses a different mix of chemicals based on site conditions and local geology. As such, some companies provide full voluntary disclosure, but others claim that the composition of high-pressure fluids must be protected to safeguard their competitive advantage.

For hazardous materials, companies wishing to protect their intellectual property may apply to the Hazardous Material Information Review Commission for a claim exemption under the Hazardous Material Information Review Act to deem the ingredient or formulation a proprietary trade secret.

Alex Ferguson, vice-president of policy and performance for the Canadian Association of Petroleum Producers in Calgary, says the determination of which ingredients are considered trade secrets falls under federal jurisdiction. “It is not a common thing,” he notes. “It is just a mechanism for the federal government to recognize there is a business interest here, and we want to make sure that people are competitively doing new research on new things.” He adds that the industry is “mindful” of the chemicals that are injected into the ground. “There is a pretty big move towards eliminating toxicity from the components as new research is being done.”

For instance, oilfield service company Halliburton’s CleanStream™ System uses ultraviolet-light technology to control bacteria in oilfield and pipeline applications, while minimizing or eliminating the need for hazardous biocides. Fluid flowing through specialized chambers in a mobile unit is irradiated with ultraviolet light, which is absorbed into the bacteria’s cell wall and damages its DNA structure, killing the bacteria colony. Information from the company says the process reduces employee exposure to hazard-rated biocides and that practical application of the CleanStream™ technology has been ongoing since April 2009.

But critics who oppose the disclosure exemption abound. “I think there needs to be full disclosure of the use of chemicals. I don’t even think it is in the industry’s interest to maintain a high level of secrecy,” Dr. Stringfellow contends.

Dr. Bharadwaj agrees. “A better understanding of what concentration of chemicals and the identity of those chemicals we are dealing with in certain media — for example, in the flowback water or even released air — gives us a better assessment of potential exposures to individuals on a workplace and also to the public.” This, in turn, can aid in the design of proper engineering controls, she adds.

Danielle Fugere, president of As You Sow, a non-profit foundation in Oakland, California that promotes environmental and social corporate responsibility, acknowledges that while FracFocus has given people access to more information on the chemicals used, trade secrets are still allowed.

“In some ways, they are prone to allow that without a hard look into whether that is really a trade secret and what they can really do to perhaps preserve the secrecy, or is there some way to get the information out in a way that it doesn’t reveal formulations,” Fugere notes. She adds that it is “critically important” to compel that information to be made public. “You take less precaution if the public does not know specifically what type of harmful chemicals are being used.”

A Clouded Picture
A report that benchmarks 24 companies in the United States and Canada engaging in hydraulic-fracturing activities against investor needs for disclosure of operational impacts and mitigation efforts says the oil-and-gas production industry consistently fails to report measurable reductions of its effects on communities and the environment from fracking operations. Disclosing Facts: Transparency and Risks in Hydraulic Fracturing Operations, which addresses onshore operations in North America from January 2012 to August 2013, is a collaborative effort of As You Sow, Boston Common Asset Management, Green Century Capital Management and the Investor Environmental Health Network.

Findings indicate that not a single firm succeeded in disclosing information on even half of the selected 32 indicators related to management of toxic chemicals, water and waste, air emissions, community impacts and governance. The highest-scoring company, Encana Corporation, provided sufficient disclosure on just 14 out of 32 indicators. Quantifiable data are lacking, and much of the disclosure by companies is narrative and qualitative in form.

As well, only four of the companies surveyed clearly state on their websites that some of the chemicals used were protected by confidentiality claims and thus were not disclosed. Many of the industry’s website representations about disclosure of fracking chemicals are incorrect to the extent that they convey an expectation that chemical disclosure is complete when, in fact, it is not, the report concludes.

“A lot of the issues that are addressed in the report also bear on worker safety to the extent that [if] you have got open-pit and air-quality problems affecting homeowners, you are also going to have air-quality problems that are affecting the workers,” Fugere argues. She attributes the lack of transparency to a number of reasons.

“One is simply that companies simply do not like to, in essence, go public with what they are doing,” she suggests. “That way, they cannot be held to any standards.” The resources required to compile, report and update relevant data is another contributing factor. That said, she observes increasing pressure on companies to disclose their practices.

“Knowing what those chemicals are is incredibly important to people whose water supply may be harmed and be able to trace those back to the companies that are putting the chemicals in the water.” Transparency through disclosure also allows companies to share their best practices and set a standard for other companies, she adds.

The report recommends reducing the toxicity of fracking fluids, reporting quantitatively on progress in toxicity reduction and clarifying when confidential-business-information claims prevent full disclosure of chemicals used.

Turning the Tide
The wind of change is blowing. The United States’ Environmental Protection Agency announced on May 9 that it would initiate a public participation process to seek comment on the information that should be disclosed for fracking chemical substances and the mechanism for obtaining this information.

On the corporate front, drilling-services company Baker Hughes Incorporated in Houston announced on October 1 that it had implemented a new policy of disclosing 100 per cent of the chemistry contained within its hydraulic-fracturing fluid systems without the use of trade-secret designations.

Here at home, the Northwest Territories (NWT) announced on June 2 the development of regulations under the NWT Oil and Gas Operations Act that set out filing requirements for projects involving hydraulic fracturing. On September 30, Nova Scotia introduced amendments to the Petroleum Resources Act, which will place a moratorium on high-volume hydraulic fracturing for onshore oil and gas shale development. In October, Newfoundland and Labrador announced the names of five individuals appointed to an independent panel that will conduct a review of the socio-economic and environmental implications of fracking in western Newfoundland. A final report, due in a year’s time, will be made available to the public.

“I suggest full, mandatory disclosure of all chemicals and amounts used,” Dr. Stringfellow says. “The composition of the chemical and additive mixtures should be known and there is no reason a safety plan should not include hydraulic-fracturing chemicals.”

Jean Lian is editor of OHS CANADA.

Follow us on Twitter @OHSCanada

On the Road

Well sites are not the only places where workers can be put in harm’s way. Operating vehicles that service oil wells have proven just as precarious. The number of truck trips required to supply water and fracking chemicals to, and transport waste water from, a horizontally-drilled well site can run up to the thousands. “It is a very crowded place, so there could be potential for accidents to occur,” suggests Lalita Bharadwaj, Ph.D., associate professor with the School of Public Health at the University of Saskatchewan in Saskatoon.

According to the Centers for Disease Control and Prevention in Washington, D.C., increases in oil-and-gas extraction activity correlated with a hike in the industry’s rate of fatal occupational injuries. From 2003 to 2006, there were 404 work-related fatalities among oil and gas extraction workers in the United States, which translates into an average annual fatality rate of 30.5 per 100,000 workers — roughly seven times the rate for all workers. Nearly half of all fatal injuries among these workers were attributed to highway motor-vehicle crashes and machinery striking workers.

The dangers on the road are further compounded by oil-field exemptions from highway-safety rules that allow truckers servicing the oil and gas sector in Canada and the United States to work longer hours than drivers in most other industries do. Transport Canada exempts extra-provincial truck undertakings or federal carriers and their drivers of oil-well-service vehicles from the hours-of-service off-duty requirements stipulated in Sections 13 and 14 of the Commercial Vehicle Drivers Hours of Service Regulations.

A company wishing to operate under the exemptions must have a valid Oil Well Service Vehicle Permit issued by one of the western provinces — British Columbia, Alberta, Saskatchewan and Manitoba — in addition to meeting other requirements set out in the exemptions. The purpose of the exemptions is to allow drivers to meet the mandatory off-duty and daily off-duty time requirements by accumulating off-duty time in sleeper berths or in alternate sleep accommodations.

Alex Ferguson, vice-president of policy and performance for the Canadian Association of Petroleum Producers in Calgary, says the industry is mindful of the dangers associated with production activities, and that the western provinces are focusing on how to manage those processes. “We are seeing more and more alignment, especially in western Canada.”



Stories continue below

Print this page

Related Stories