In Europe, Poland, Norway and Germany have the largest reserves of shale gas, and drillings are underway.[2]
In the United Kingdom, the environmental regulator permits only chemical additives which are classed as non hazardous to groundwater for fracturing fluids.[3][4][5] Operators are required to disclose the content of hydraulic fracturing fluids to the relevant environment agency[6] while the composition must be disclosed if the regulator demands it.[7] The permitted additives for hydraulic fracturing fluid include polycrylamide, hydrochloric acid and a biocide.
In the US, about 750 compounds have been listed as additives for hydraulic fracturing, also known as ingredients of pressurized fracking fluid,[9] in an industry report to the US Congress in 2011 after originally being kept secret for "commercial reasons".[10][11] The following is a partial list of the chemical constituents in additives that are used or have been used in fracturing operations, as based on the report of the New York State Department of Environmental Conservation, some are known to be carcinogenic.[12]
| CAS Number | Chemical Constituent | Commercial use [8] | | 2634-33-5 | 1,2-Benzisothiazolin-2-one / 1,2-benzisothiazolin-3-one | Insecticide Spray, Stain Remover}} |
| 95-63-6 | 1,2,4-trimethylbenzene | Automatic Transmission Sealer |
| 123-91-1 | 1,4-Dioxane | Wood Parquet Adhesive |
| 3452-07-1 | 1-eicosene | No record |
| 629-73-2 | 1-hexadecene | No record |
| 112-88-9 | 1-octadecene | No record |
| 1120-36-1 | 1-tetradecene | Stain Remover |
| 10222-01-2 | 2,2 Dibromo-3-nitrilopropionamide, a biocide | No record |
| 27776-21-2 | 2,2'-azobis2-(imidazlin-2-yl)propanedihydrochloride | No record |
| 73003-80-2 | 2,2-Dibromomalonamide | No record |
| 15214-89-8 | 2-Acrylamido-2-methylpropane sulphonic acid sodium salt polymer | No record |
| 46830-22-2 | 2-acryloyloxyethyl(benzyl)dimethylammonium chloride | No record |
| 52-51-7 | 2-Bromo-2-nitro-1,3-propanediol | Deodorant, Conditioner |
| 111-76-2 | 2-Butoxy ethanol | Engine Cleaner |
| 1113-55-9 | 2-Dibromo-3-Nitriloprionamide (2-Monobromo-3-nitriilopropionamide) | No record |
| 104-76-7 | 2-Ethyl Hexanol | Diesel Fuel Treatment |
| 67-63-0 | 2-Propanol / Isopropyl Alcohol / Isopropanol / Propan-2-ol | Damar Varnish, Gloss |
| 26062-79-3 | 2-Propen-1-aminium, N,N-dimethyl-N-2-propenyl-chloride, homopolymer | Volumizing Conditioner |
| 9003-03-6 | 2-propenoic acid, homopolymer, ammonium salt | Moisturizer, Sunscreen |
| 25987-30-8 | 2-Propenoic acid, polymer with 2 p-propenamide, sodium salt / Copolymer of acrylamide and sodium acrylate | No record |
| 71050-62-9 | 2-Propenoic acid, polymer with sodium phosphinate (1:1) | No record |
| 66019-18-9 | 2-propenoic acid, telomer with sodium hydrogen sulfite | No record |
| 107-19-7 | 2-Propyn-1-ol / Propargyl alcohol | No record |
| 51229-78-8 | 3,5,7-Triaza-1-azoniatricyclo[3.3.1.13,7]decane, 1-(3-chloro-2-propenyl)-chloride, | Clean Pressed Powder |
| 115-19-5 | 3-methyl-1-butyn-3-ol | No record |
| 127087-87-0 | 4-Nonylphenol Polyethylene Glycol Ether Branched / Nonylphenol ethoxylated / Oxyalkylated Phenol | Chrome Wheel Cleaner |
| 64-19-7 | Acetic acid | Silicone Sealant |
| 68442-62-6 | Acetic acid, hydroxy-, reaction products with triethanolamine | No record |
| 108-24-7 | Acetic Anhydride | No record |
| 67-64-1 | Acetone | Solvent, Clear Finish Gloss |
| 38193-60-1 | Acrylamide – sodium 2-acrylamido-2-methylpropane sulfonate copolymer | Moisture, Lotion |
| 25085-02-3 | Acrylamide – Sodium Acrylate Copolymer or Anionic Polyacrylamide | No record |
| 25987-30-8 | 2-Propenoic acid, polymer with 2-propenamide, sodium salt | No record |
| 69418-26-4 | Acrylamide polymer with N,N,N-trimethyl-2[1-oxo-2-propenyl]oxy Ethanaminium chloride | No record |
| 15085 | −02-3 Acrylamide-sodium acrylate copolymer | No record |
| 68551-12-2 | Alcohols, C12-C16, Ethoxylated (a.k.a. Ethoxylated alcohol) | Floor Cleaner, Stain Remover |
| 64742-47-8 | Aliphatic Hydrocarbon / Hydrotreated light distillate / Petroleum Distillates / Isoparaffinic Solvent / Paraffin Solvent / Napthenic Solvent | Tar Remover, Lubricant |
| 64743-02-8 | Alkenes | No record |
| 68439-57-6 | Alkyl (C14-C16) olefin sulfonate, sodium salt | Car Wash, Dog Shampoo |
| 9016-45-9 | Alkylphenol ethoxylate surfactants | Engine Cleaner, Rubber Sealant |
| 1327-41-9 | Aluminum chloride | Antiperspirant |
| 73138-27-9 | Amines, C12-14-tert-alkyl, ethoxylated | No record |
| 71011-04-6 | Amines, Ditallow alkyl, ethoxylated | No record |
| 68551-33-7 | Amines, tallow alkyl, ethoxylated, acetates | No record |
| 1336-21-6 | Ammonia | Stripper, Glue, Tire Repair |
| 631-61-8 | Ammonium acetate | Haircolor Shine |
| 68037-05-8 | Ammonium Alcohol Ether Sulfate | No record |
| 7783-20-2 | Ammonium bisulfate | Ant Killer, Weed & Moss Control |
| 10192-30-0 | Ammonium bisulfite | No record |
| 12125-02-9 | Ammonium chloride | Brass & Copper Polish, Bleach |
| 7632-50-0 | Ammonium citrate | No record |
| 37475-88-0 | Ammonium Cumene Sulfonate | No record |
| 1341-49-7 | Ammonium hydrogen-difluoride | Wheel Cleaner, Glass Etching |
| 6484-52-2 | Ammonium nitrate | Moisture Control, Ink Cartridge |
| 7727-54-0 | Ammonium Persulfate / Diammonium peroxidisulphate | Latex Paint, Maximizing Powder |
| 1762-95-4 | Ammonium Thiocyanate | Liquid Hide Glue |
| 7664-41-7 | Aqueous ammonia | Paint Stripper, Caulk |
| 121888-68-4 | Bentonite, benzyl(hydrogenated tallow alkyl) dimethylammonium stearate complex / organophilic clay | Wine clearing agent, "Detox" Product |
| 71-43-2 | Benzene | Fuel System Cleaner, Degreaser |
| 119345-04-9 | Benzene, 1,1'-oxybis, tetratpropylene derivatives, sulfonated, sodium salts | Toilet Cleaner, Rust Neutralizer |
| 74153-51-8 | Benzenemethanaminium, N,N-dimethyl-N-[2-[(1-oxo-2-propenyl)oxy]ethyl]-, chloride, polymer with 2-propenamide | No record |
| 10043-35-3 | Boric acid | Roach Killer, Stain Remover |
| 1303-86-2 | Boric oxide / Boric Anhydride | Carpenters Glue |
| 71-36-3 | Butan-1-ol | Interior/Exterior Paint |
| 68002-97-1 | C10 – C16 Ethoxylated Alcohol | Floor Finish Remover, Degreaser |
| 68131-39-5 | C12-15 Alcohol, Ethoxylated | Graffiti Remover, Radiator Flush |
| 10043-52-4 | Calcium chloride | Chlorinating Sanitizer, Ice Melt |
| 124-38-9 | Carbon dioxide | Penetrant, Lubricator |
| 68130-15-4 | Carboxymethylhydroxypropyl guar | No record |
| 9012-54-8 | Cellulase / Hemicellulase Enzyme |
| 9004-34-6 | Cellulose |
| 10049-04-4 | Chlorine dioxide |
| 77-92-9 | Citric Acid |
| 94266-47-4 | Citrus Terpenes |
| 61789-40-0 | Cocamidopropyl betaine |
| 68155-09-9 | Cocamidopropylamine Oxide |
| 68424-94-2 | Coco-betaine |
| 7758-98-7 | Copper(II) sulfate |
| 31726-34-8 | Crissanol A-55 |
| 14808-60-7 | Crystalline Silica (Quartz) |
| 7447-39-4 | Cupric chloride dihydrate |
| 1120-24-7 | Decyldimethyl Amine |
| 2605-79-0 | Decyl-dimethyl Amine Oxide |
| 3252-43-5 | Dibromoacetonitrile |
| 25340-17-4 | Diethylbenzene |
| 111-46-6 | Diethylene glycol |
| 22042-96-2 | Diethylenetriamine penta (methylenephonic acid) sodium salt |
| 28757-00-8 | Diisopropyl naphthalenesulfonic acid |
| 68607-28-3 | Dimethylcocoamine, bis(chloroethyl) ether, diquaternary ammonium salt |
| 7398-69-8 | Dimethyldiallylammonium chloride |
| 25265-71-8 | Dipropylene glycol |
| 139-33-3 | Disodium Ethylene Diamine Tetra Acetate |
| 5989-27-5 | D-Limonene |
| 123-01-3 | Dodecylbenzene |
| 27176-87-0 | Dodecylbenzene sulfonic acid |
| 42504-46-1 | Dodecylbenzenesulfonate isopropanolamine |
| 50-70-4 | D-Sorbitol / Sorbitol |
| 37288-54-3 | Endo-1,4-beta-mannanase, or Hemicellulase |
| 149879-98-1 | Erucic Amidopropyl Dimethyl Betaine |
| 89-65-6 | Erythorbic acid, anhydrous |
| 54076-97-0 | Ethanaminium, N,N,N-trimethyl-2-[(1-oxo-2-propenyl)oxy]-, chloride, homopolymer |
| 107-21 | −1 Ethane-1,2-diol / Ethylene Glycol |
| 9002-93-1 | Ethoxylated 4-tert-octylphenol |
| 68439-50-9 | Ethoxylated alcohol |
| 126950-60-5 | Ethoxylated alcohol |
| 67254-71-1 | Ethoxylated alcohol (C10-12) |
| 68951-67-7 | Ethoxylated alcohol (C14-15) |
| 68439-46-3 | Ethoxylated alcohol (C9-11) |
| 66455-15-0 | Ethoxylated Alcohols |
| 84133-50-6 | Ethoxylated Alcohols (C12-14 Secondary) |
| 68439-51-0 | Ethoxylated Alcohols (C12-14) |
| 78330-21-9 | Ethoxylated branch alcohol |
| 34398-01-1 | Ethoxylated C11 alcohol |
| 61791-12-6 | Ethoxylated Castor Oil |
| 61791-29-5 | Ethoxylated fatty acid, coco |
| 61791-08-0 | Ethoxylated fatty acid, coco, reaction product with ethanolamine |
| 68439-45-2 | Ethoxylated hexanol |
| 9036-19-5 | Ethoxylated octylphenol |
| 9005-67-8 | Ethoxylated Sorbitan Monostearate |
| 9004-70-3 | Ethoxylated Sorbitan Trioleate |
| 64-17-5 | Ethyl alcohol / ethanol |
| 100-41-4 | Ethyl Benzene |
| 97-64-3 | Ethyl lactate |
| 9003-11-6 | Ethylene Glycol-Propylene Glycol Copolymer (Oxirane, methyl-, polymer with oxirane) |
| 75-21-8 | Ethylene oxide |
| 5877-42-9 | Ethyloctynol |
| 68526-86-3 | Exxal 13 |
| 61790-12-3 | Fatty Acids |
| 68188-40-9 | Fatty acids, tall oil reaction products w/ acetophenone, formaldehyde & thiourea |
| 9043-30-5 | Fatty alcohol polyglycol ether surfactant |
| 7705-08-0 | Ferric chloride |
| 7782-63-0 | Ferrous sulfate, heptahydrate |
| 50-00-0 | Formaldehyde |
| 29316-47-0 | Formaldehyde polymer with 4,1,1-dimethylethyl phenolmethyl oxirane |
| 153795-76-7 | Formaldehyde, polymers with branched 4-nonylphenol, ethylene oxide and propylene oxide |
| 75-12-7 | Formamide |
| 64-18-6 | Formic acid |
| 110-17-8 | Fumaric acid |
| 65997-17-3 | Glassy calcium magnesium phosphate |
| 111-30-8 | Glutaraldehyde |
| 56-81-5 | Glycerol / glycerine |
| 9000-30-0 | Guar Gum |
| 64742-94-5 | Heavy aromatic petroleum naphtha |
| 9025-56-3 | Hemicellulase |
| 7647-01-0 | Hydrochloric Acid / Hydrogen Chloride / muriatic acid | Toilet Bowl Cleaner |
| 7722-84-1 | Hydrogen peroxide |
| 79-14-1 | Hydroxy acetic acid |
| 35249-89-9 | Hydroxyacetic acid ammonium salt |
| 9004-62-0 | Hydroxyethyl cellulose |
| 5470-11-1 | Hydroxylamine hydrochloride |
| 39421-75-5 | Hydroxypropyl guar |
| 35674-56-7 | Isomeric Aromatic Ammonium Salt |
| 64742-88-7 | Isoparaffinic Petroleum Hydrocarbons, Synthetic |
| 64-63-0 | Isopropanol |
| 98-82-8 | Isopropylbenzene (cumene) |
| 68909-80-8 | Isoquinoline, reaction products with benzyl chloride and quinoline |
| 8008-20-6 | Kerosene |
| 64742-81-0 | Kerosine, hydrodesulfurized |
| 63-42-3 | Lactose |
| 64742-95-6 | Light aromatic solvent naphtha |
| 1120-21-4 | Light Paraffin Oil |
| 14807-96-6 | Magnesium Silicate Hydrate (Talc) |
| 1184-78-7 | methanamine, N,N-dimethyl-, N-oxide |
| 67-56-1 | Methanol |
| 68891-11-2 | Methyloxirane polymer with oxirane, mono (nonylphenol) ether, branched |
| 8052-41-3 | Mineral spirits / Stoddard Solvent |
| 141-43-5 | Monoethanolamine |
| 44992-01-0 | N,N,N-trimethyl-2[1-oxo-2-propenyl]oxy Ethanaminium chloride |
| 64742-48-9 | Naphtha (petroleum), hydrotreated heavy |
| 91-20-3 | Naphthalene |
| 38640-62-9 | Naphthalene bis(1-methylethyl) |
| 93-18-5 | Naphthalene, 2-ethoxy- |
| 68909-18-2 | N-benzyl-alkyl-pyridinium chloride |
| 68139-30-0 | N-Cocoamidopropyl-N,N-dimethyl-N-2-hydroxypropylsulfobetaine |
| 7727-37-9 | Nitrogen, Liquid form |
| 68412-54-4 | Nonylphenol Polyethoxylate |
| 121888-66-2 | Organophilic Clays |
| 64742-65-0 | Petroleum Base Oil |
| 64741-68-0 | Petroleum naphtha |
| 70714-66-8 | Phosphonic acid, (phosphonomethyl)iminobis2,1-ethanediylnitrilobis(methylene)tetrakis-, ammonium salt |
| 8000-41-7 | Pine Oil |
| 60828-78-6 | Poly(oxy-1,2-ethanediyl), a-[3,5-dimethyl-1-(2-methylpropyl)hexyl]-w-hydroxy- |
| 25322-68-3 | Poly(oxy-1,2-ethanediyl), a-hydro-w-hydroxy / Polyethylene Glycol |
| 24938-91-8 | Poly(oxy-1,2-ethanediyl), α-tridecyl-ω-hydroxy- |
| 51838-31-4 | Polyepichlorohydrin, trimethylamine quaternized |
| 56449-46-8 | Polyethlene glycol oleate ester |
| 62649-23-4 | Polymer with 2-propenoic acid and sodium 2-propenoate |
| 9005-65-6 | Polyoxyethylene Sorbitan Monooleate |
| 61791-26-2 | Polyoxylated fatty amine salt |
| 127-08-2 | Potassium acetate |
| 12712-38-8 | Potassium borate |
| 1332-77-0 | Potassium borate |
| 20786-60-1 | Potassium Borate |
| 584-08-7 | Potassium carbonate |
| 7447-40-7 | Potassium chloride |
| 590-29-4 | Potassium formate |
| 1310-58-3 | Potassium Hydroxide |
| 13709-94-9 | Potassium metaborate |
| 24634-61-5 | Potassium sorbate |
| 112926-00-8 | Precipitated silica / silica gel |
| 57-55-6 | Propane-1,2-diol, or Propylene glycol |
| 107-98-2 | Propylene glycol monomethyl ether |
| 68953-58-2 | Quaternary Ammonium Compounds |
| 62763-89-7 | Quinoline,2-methyl-, hydrochloride |
| 15619-48-4 | Quinolinium, 1-(phenylmethl),chloride |
| 7631-86-9 | Silica, Dissolved |
| 5324-84-5 | Sodium 1-octanesulfonate |
| 127-09-3 | Sodium acetate |
| 95371-16-7 | Sodium Alpha-olefin Sulfonate |
| 532-32-1 | Sodium benzoate |
| 144-55-8 | Sodium bicarbonate |
| 7631-90-5 | Sodium bisulfate |
| 7647-15-6 | Sodium bromide |
| 497-19-8 | Sodium carbonate |
| 7647-14-5 | Sodium Chloride |
| 7758-19-2 | Sodium chlorite |
| 3926-62-3 | Sodium chloroacetate |
| 68-04-2 | Sodium citrate |
| 6381-77-7 | Sodium erythorbate / isoascorbic acid, sodium salt |
| 2836-32-0 | Sodium Glycolate |
| 1310-73-2 | Sodium Hydroxide |
| 7681-52-9 | Sodium hypochlorite |
| 7775-19-1 | Sodium Metaborate .8H2O |
| 10486-00-7 | Sodium perborate tetrahydrate |
| 7775-27-1 | Sodium persulfate |
| 9003-04-7 | Sodium polyacrylate |
| 7757-82-6 | Sodium sulfate |
| 1303-96-4 | Sodium tetraborate decahydrate |
| 7772-98-7 | Sodium thiosulfate |
| 1338-43-8 | Sorbitan Monooleate |
| 57-50-1 | Sucrose |
| 5329-14-6 | Sulfamic acid |
| 112945-52-5 | Synthetic Amorphous / Pyrogenic Silica / Amorphous Silica |
| 68155-20-4 | Tall Oil Fatty Acid Diethanolamine |
| 8052-48-0 | Tallow fatty acids sodium salt |
| 72480-70-7 | Tar bases, quinoline derivs., benzyl chloride-quaternized |
| 68647-72-3 | Terpene and terpenoids |
| 68956-56-9 | Terpene hydrocarbon byproducts |
| 533-74-4 | Tetrahydro-3,5-dimethyl-2H-1,3,5-thiadiazine-2-thione (a.k.a. Dazomet) |
| 55566-30-8 | Tetrakis(hydroxymethyl)phosphonium sulfate (THPS) |
| 75-57-0 | Tetramethyl ammonium chloride |
| 64-02-8 | Tetrasodium Ethylenediaminetetraacetate |
| 68-11-1 | Thioglycolic acid |
| 62-56-6 | Thiourea |
| 68527-49-1 | Thiourea, polymer with formaldehyde and 1-phenylethanone |
| 108-88-3 | Toluene |
| 81741-28-8 | Tributyl tetradecyl phosphonium chloride |
| 68299-02-5 | Triethanolamine hydroxyacetate |
| 112-27-6 | Triethylene glycol |
| 52624-57-4 | Trimethylolpropane, Ethoxylated, Propoxylated |
| 150-38-9 | Trisodium Ethylenediaminetetraacetate |
| 5064-31-3 | Trisodium Nitrilotriacetate |
| 7601-54-9 | Trisodium orthophosphate |
| 57-13-6 | Urea |
| 25038-72-6 | Vinylidene Chloride/Methylacrylate Copolymer |
| 7732-18-5 | Water | Deionized water |
| 1330-20-7 | Xylene | Carburetor Cleaner, Asphalt Primer |
| 068604-95-5 | Aliphatic acids | Wall & Trim Enamel |
| 078330-20-8 | Aliphatic Ethoxylated Alcohols | Leather Cleaner |
| 000000-33-9 | Alkyl aryl polyethoxy alcohols | Coppersmiths Polish |
| 000000-17-6 | Alkylaryl Sulfonate | Detergent, Stain Remover |
| 064742-47-8 | Distillates, petroleum, hydrotreated light | Tar Remover, Sealant |
| 000110-43-0 | Methyl n-amyl & ethyl ketones | Hobby Cement, Sealant |
| Oxyalkylated alkylphenol |
| Petroleum distillate blend |
| Polyethoxylated alkanol |
| Polymeric Hydrocarbons |
| Salt of amine-carbonyl condensate |
| Salt of fatty acid/polyamine reaction product |
| Sugar |
| Surfactant blend |
1. ^{{cite web|last1=Soraghan|first1=Mike|title=Halliburton Announces Ecofriendly Fracking Fluid, More Disclosure|url=https://www.nytimes.com/gwire/2010/11/15/15greenwire-halliburton-announces-ecofriendly-fracking-flu-80875.html?pagewanted=all|website=The New York Times|accessdate=13 April 2017|date=15 November 2010|quote=Halliburton Co., which is fighting U.S. EPA about disclosure of its hydraulic fracturing fluid, today announced that it will publicly disclose detailed information on its website about the chemicals used in its fracturing fluids. The Houston-based oilfield services company announced the creation of a new fracturing fluid that uses chemicals "sourced entirely from the food industry."}}
2. ^{{cite journal |title=Hydraulic Fracturing or ‘Fracking’: A Short Summary of Current Knowledge and Potential Environmental Impacts |format=PDF |pages=18–19 |author=Dr Dave Healy |date=July 2012 |publisher=Department of Geology & Petroleum Geology, University of Aberdeen |url=https://www.epa.ie/pubs/reports/research/sss/UniAberdeen_FrackingReport.pdf |accessdate=12 November 2015}}
3. ^{{cite web|title=The Environmental Permitting (England and Wales) Regulations 2010|url=http://www.legislation.gov.uk/ukdsi/2010/9780111491423/schedule/22|publisher=UK Government|year=2010|accessdate= 2016-08-28}}
4. ^{{cite web|title=The Pollution Prevention and Control (Scotland) Regulations 2012|url=http://www.legislation.gov.uk/ssi/2012/360/schedule/5/made|website=www.legislation.gov.uk|publisher=Queen's Printer for Scotland (QPS)|accessdate=1 April 2017|language=en}}
5. ^{{cite web|title=DIRECTIVE 2006/118/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 12 December 2006 on the protection of groundwater against pollution and deterioration|url=http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32006L0118|website=eur-lex.europa.eu|publisher=EUR-Lex - 32006L0118 - EN - EUR-Lex|accessdate=18 October 2014|language=en|date=12 December 2006|quote=It is necessary to distinguish between hazardous substances, inputs of which should be prevented, and other pollutants, inputs of which should be limited. Annex VIII to Directive 2000/60/EC, listing the main pollutants relevant for the water environment, should be used to identify hazardous and non-hazardous substances which present an existing or potential risk of pollution.}}
6. ^{{cite web|title=Onshore oil and gas exploration in the UK: regulation and best practice|url=https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/503067/Onshore_UK_oil_and_gas_exploration_England_Dec15.pdf|page=46|format=PDF|quote=Operators will disclose the chemical additives of fracturing fluids on a well-by-well basis.|publisher=DECC/BEIS|accessdate=13 April 2017}}
7. ^{{cite report|url=http://royalsociety.org/uploadedFiles/Royal_Society_Content/policy/projects/shale-gas/2012-06-28-Shale-gas.pdf |first=Robert |last=Mair |title=Shale gas extraction in the UK: A review of hydraulic fracturing |publisher=The Royal Society and the Royal Academy of Engineering|date=June 2012|accessdate=3 April 2017 |format=PDF}}
8. ^1 {{cite web |url=http://hpd.nlm.nih.gov/cgi-bin/household/search?tbl=TblChemicals&queryx=7647-01-0 |title=Household Products Database |work=Health and Safety Information on Household Products |publisher=U.S. Department of Health and Human Services |date=August 2015 |accessdate=11 November 2015 |author=NLM }}
9. ^{{cite web |url=https://fracfocus.org/chemical-use/what-chemicals-are-used |title=What chemicals are used in a hydraulic fracturing job |publisher=FracFocus |work=Chemical Disclosure Registry |author=GWPC & IOGCC |year=2015 |accessdate=11 November 2015}}
10. ^{{cite web| url=https://www.propublica.org/article/fracking-chemicals-cited-in-congressional-report-stay-underground/single| author=Nicholas Kusnetz| title=Fracking Chemicals Cited in Congressional Report Stay Underground |publisher=ProPublica| date=April 8, 2011 |accessdate=July 11, 2011}}
11. ^{{cite report|url=http://democrats.energycommerce.house.gov/sites/default/files/documents/Hydraulic-Fracturing-Chemicals-2011-4-18.pdf |publisher=Committee on Energy and Commerce U.S. House of Representatives |title=Chemicals Used in Hydraulic Fracturing |date=April 18, 2011 |format=PDF |deadurl=yes |archiveurl=https://web.archive.org/web/20131004213846/http://democrats.energycommerce.house.gov/sites/default/files/documents/Hydraulic-Fracturing-Chemicals-2011-4-18.pdf |archivedate=October 4, 2013 |df= }}
12. ^{{cite web|url=http://www.dec.ny.gov/docs/materials_minerals_pdf/ogdsgeischap5.pdf|title=Natural Gas Development Activities and High‐volume Hydraulic Fracturing|publisher=New York State Department of Environmental Conservation|pages=45–51 |date=30 September 2009}}
{{Hydraulic fracturing 2}}{{DEFAULTSORT:Additives For Hydraulic Fracturing}}