The industrial scale use of potentially dangerous chemical compounds in shale and tight gas fracking operations can have serious consequences for human and animal health. The industry maintains that it uses "a small number of additives in fraccing fluid, all of which you will find in a typical household in items you may use, such as food and cleaning products".
The National Toxics Network (NTN) says that a review of the health impacts associated with some of the chemicals used in fracking shows they are far from non-toxic. In fact many are unsafe for human health or release into the environment.
These include carcinogens (eg naphthalene), neurotoxins (eg isopropanol), irritants/sensitisers (eg sodium persulfate), reproductive toxins (eg ethylene glycol) and endocrine disruptors (eg nonylphenol).
Some of the chemicals were found to be dangerous at concentrations near or below chemical detection limits (eg glutaraldehyde, brominated biocides (DBNPA, DBAN), propargyl alcohol, 2-butoxyethanol (2-BE), heavy naphtha.)
A number of chemicals used in hydraulic fracturing have recently been identified as endocrine disrupters. These include ethylene glycol monobutyl ether, 2-ethylhexanol, ethylene glycol, diethanolamine, diethylene glycol methyl ether, sodium tetraborate decahydrate, 1,2-bromo-2-nitropropane-1,3-diol, n,n-dimethyl formamide, cumene, and styrene.
The APPEA website provides a list of chemicals approved for use in fracking operations in Australia. The Queensland Government's Department of Environment and Heritage Protection includes a list of chemicals approved for use in that state.
Material Safety Data Sheets
Material Safety Data Sheets (MSDS) provide workers and emergency personnel with procedures for the safe use, handling and storage of hazardous substances. MSDS include information on the toxicity, health effects, first aid, reactivity, storage, disposal, protective equipment, and spill-handling procedures, as well as physical data such as the melting point, boiling point, flash point, etc., and a chemical's effects in the environment.
Some of the health effects of the chemicals APPEA says are approved for use in fracking operations in Australia are described in our Chemical List.
The National Industrial Chemicals Notification and Assessment Scheme (NICNAS) is due to report on the use and potential risks of fracking chemicals in mid-2015. The National Assessment will:
- develop an understanding among stakeholders of the public, occupational and environmental risks arising from chemicals used in drilling and hydraulic fracturing for CSG extraction in Australia
- provide an evidence base for the appropriate management of chemicals as part of the broader management of CSG activities
- improve public access to information about chemicals used in hydraulic fracturing operations
As well as chemicals, state governments in Australia have issued a radiation management licence to at least one fracking company, US drilling company Halliburton. The licence permits the use caesium-137, a radioactive isotope, for drilling by AGL at Gloucester, in the northern Hunter Valley and for Santos in the Pilliga forests near Narrabri. CS-137 is produced in nuclear power plants and is potentially deadly. It is one of the main radiation concerns at failed power stations at Chernobyl and Fukushima.
An anti-coal seam gas campaigner at Gloucester in NSW, Jennifer Schoelpple, said that while the company stressed the benign nature of fracking chemicals at community meetings:
No matter how thoroughly you search 'under your kitchen sink' or how scrupulously you check the ingredients of your 'household products', you are highly unlikely to lay your hands on any CS-137 in your family home.
In 2014 scientists at the National Meeting and Exposition of the American Chemical Society (ACS) examined a list of substances commonly used in fracking, including:
- Gelling agents to thicken fracking fluids
- Biocides to prevent microbial growth
- Sand & ceramic beads used to prop open fractures in rocks
- Compounds to prevent corrosion
Their analysis found that out of nearly 200 commonly used compounds, very little is known about the potential health risks of about one-third, and eight are known to be toxic to mammals. Many chemicals, such as corrosion inhibitors and biocides, which are used in high concentrations, have particularly adverse effects. For example, as the chemists noted biocides are designed to kill bacteria. They are not a benign material.
A 2012 case study in the US found serious evidence of harm to domestic stock from shale gas drilling waste contamination, including cattle deaths, stillbirths and reproductive problems. In addition to concerns over the contamination of aquifers from the chemicals added to fracking fluid, issues have also been raised about contamination of water supplies from fugitive gas after fracking.
What are they putting down there? Why do fracking operations use so many potentially harmful additives? What are the chemicals used for?
Proppant: [Sand; sintered bauxite; zirconium oxide; ceramic beads]
"Props" open fractures and allows gas / fluids to flow more freely to the well bore.
Acid: [Hydrochloric acid (HCl, 3% to 28%); muriatic acid]
Cleans up perforation intervals of cement and drilling mud prior to fracturing fluid injection, and provides accessible pathways to the formation.
Reduces the viscosity of the fracking mix in order to release the sand or proppant into fractures and enhance the recovery of the fracking fluid.
Bactericide / Biocide: [Gluteraldehyde; 2-Bromo-2-nitro-1,2-propanediol]
Inhibits the growth of organisms that could contaminate the gas; and prevents the growth of bacteria which can reduce the ability of fracking fluid to carry the proppant into fractures.
Buffer / pH Adjusting Agent: [Sodium or potassium carbonate; acetic acid]
Adjusts and controls the pH of fracking fluid to optimise the effectiveness of other additives such as crosslinkers.
Clay Stabilizer / Control: [Salts eg., tetramethyl ammonium chloride; Potassium chloride]
Prevents swelling and migration of formation clays which could block pore spaces and reduce permeability.
Corrosion Inhibitor: [Methanol; ammonium bisulfate for Oxygen Scavengers]
Reduces rust formation on steel tubing, well casings, tools, and tanks (used only in fracking fluids that contain acid).
Crosslinker: [Potassium hydroxide; borate salts; Sodium acrylate-acrylamide copolymer]
Increases viscosity using phosphate esters combined with metals. The metals are referred to as crosslinking agents. Increased viscosity allows the fracking fluid to carry more proppant into fractures.
Friction Reducer: [polyacrylamide; petroleum distillates]
Allows fracking fluids to be injected at optimum rates and pressures by minimising friction.
Gelling Agent: [Guar gum; petroleum distillate]
Increases fracking fluid viscosity, allowing the fluid to carry more proppant into fractures.
Iron Control: [Ammonium chloride; ethylene glycol; polyacrylate]
Prevents the precipitation of carbonates and sulfates (calcium carbonate, calcium sulfate, barium sulfate) which could plug off the formation.
Solvent: [Various aromatic hydrocarbons]
Additive which is soluble in oil, water and acid-based treatment fluids which is used to control the wettability of contact surfaces or to prevent or break emulsions
Surfactant: [Methanol; isopropanol; ethoxylated alcohol]
Reduces the surface tension of fracking fluids and facilitates fluid recovery.