Environment and Climate Change Canada (ECCC) substance function codes (U)

Updated in March 2026

Code: U001
Title: Abrasive
Description: Substance used to abrade, smooth, or polish an object. Used to smooth, scour, scrub, clean, wear down, or polish surfaces by rubbing against the surface and removing imperfections from a surface. Also referred to as a grinding agent; usually in the form of fine powders of hard substances. Examples include: sandstones, pumice, quartz, silicates, aluminium oxides, glass.

Code: U002
Title: Absorbent
Description: Substance used to retain other substances by assimilation. Also referred to as an antisiccative. Examples include: straw oil, alkaline solutions, kerosene. See closely related: adsorbent (U008).

Code: U003
Title: Active ingredients in cannabis products
Description: Substances used as active ingredients in cannabis products. Not active ingredients in health products (U004); active ingredients in tobacco products (U005); or active ingredients in vaping products (U006).

Code: U004
Title: Active ingredients in health products
Description: Substances used as active ingredients in natural health products, prescription or non-prescription drugs. Not active ingredients in cannabis products (U003); active ingredients in tobacco products (U005); or active ingredients in vaping products (U006).

Code: U005
Title: Active ingredients in tobacco products
Description: Substances used as active ingredients in tobacco products. Not active ingredients in health products (U004); active ingredients in cannabis products (U003); or active ingredients vaping products (U006).

Code: U006
Title: Active ingredients in vaping products
Description: Substances used as active ingredients in vaping products. Not active ingredients in health products (U004); active ingredients in cannabis products (U003); or active ingredients in tobacco products (U005).

Code: U007
Title: Adhesion/cohesion promoter
Description: Substance, either inorganic or organic, natural or synthetic, used to join opposite surfaces of differing or similar materials/substances to each other; to promote bonding between substances; to promote adhesion or cohesion of surfaces; or to fasten materials together. Generally applied from a solvent solution and allowed to dry on the two facing surfaces. Also referred to as a glue; paste; coupling agent; tackifier; gum; adhesive cement; bonding agent; inner coating; or anchor coating.

Code: U008
Title: Adsorbent
Description: Substance used to retain other substances by accumulation on their surface. Exhibits a large surface area which can attract dissolved or finely dispersed substances from another medium. Examples include: silica gel, activated alumina, activated carbon. See closely related: absorbent (U002); dehydrating agent (U039).

Code: U009
Title: Aerating or deaerating agents
Description: Substance that influences the amount of air or gases entrained in a material.

Code: U010
Title: Alloying element
Description: Elements that are added to materials/metals to modify properties such as strength, hardness, or to facilitate treatment.

Code: U011
Title: Anti-adhesive/anti-cohesive
Description: Substance that prevents or reduces the adhesion of a material to itself or to another material; prevents bonding between other substances by discouraging surface attachment; functions as the antithesis of adhesive. Also referred to as a release agent; parting agent; anti-blocking agent; slip-aid; external lubricant; anti-setoff agent; or de-dust oil. See closely related: dusting agent (U047).

Code: U012
Title: Anti-caking agent
Description: Substance that prevents granular or particulate materials from sticking or caking during transfer, storage, or use. See closely related: deflocculant (U037).

Code: U013
Title: Anti-condensation agent
Description: Substance that is used to prevent condensation on surfaces and in the atmosphere. Also referred to as an anti-dim agent; or condensation remover.

Code: U014
Title: Anti-freeze agent
Description: Substance added to fluids, especially water, to reduce the freezing point of the mixture; or applied to surfaces to melt or prevent the build-up of ice. Also referred to as a de-icing agent; or de-icer. Examples include: antifreeze liquids, windshield de-icers, aircraft de-icers, lock release agents, ice melting crystals, rock salt.

Code: U015
Title: Antioxidant
Description: Substance that retards oxidation, rancidity, deterioration, and gum formation. Used to maintain the quality, integrity, and safety of finished products by inhibiting the oxidative degradation of the ingredients in the formulation. Also referred to as an oxidation inhibitor; or anti-skinning agent.

Code: U016
Title: Anti-redeposition agent
Description: Substance that prevents dirt and grease from resettling on a cleaned surface or that helps keep soils from re-depositing onto clothing in the wash water after they have been removed. Anti-redeposition agents are water-soluble and typically negatively charged.

Code: U017
Title: Anti-scaling agent
Description: Substance added to products to prevent the build-up of inorganic oxide deposits. Prevents the build-up or removes lime scale and fouling. Also referred to as a descalers; or descaling agent. Not corrosion inhibitor (U035).

Code: U018
Title: Anti-slip agent
Description: Substance used to enhance friction between two objects. Also referred to as a friction agent.

Code: U019
Title: Anti-stain agent
Description: Substance that prevents dyes from re-depositing in the dyeing process, provides stain blocking and soil resistance in soft surface cleaners and protectors. Also referred to as a soil release agent.

Code: U020
Title: Anti-static agent
Description: Substance that prevents or reduces the tendency of a material (for example, textile, diesel fuel) to accumulate a static charge or alters the electrical properties of materials by reducing their tendency to acquire an electrical charge. Also referred to as a charge stabilizer in some applications.

Code: U021
Title: Anti-streaking agent
Description: Substance that serves to enhance evaporation or reduce film formation in order to prevent the formation of streaks on a surface during cleaning. Also referred to as a film reducer.

Code: U022
Title: Binder
Description: Substances that are either synthetic/polymeric resins that further polymerize, provide structure and cohesiveness or are substances added to compounded dry powders to provide adhesive qualities during and after compression to make tablets or cakes. Also referred to as a binding agent; or resin.

Code: U023
Title: Biocide
Description: Substance or mixture of substances used as an ingredient in a biocide. Not pest control substances (U091).

Code: U024
Title: Bleaching agent
Description: Substance that lightens or whitens a substrate through chemical reaction. Usually involves oxidative or reductive processes that decolourizes or degrades colour systems. Can occur by destroying one or more of the double bonds in the conjugated chain; by cleaving the conjugated chain; or by oxidation of one of the other moieties in the conjugated chain. Examples include: chlorine containing agents, peroxygen agents. See closely related: brightener (U025).

Code: U025
Title: Brightener
Description: Substance used to brighten, whiten, or enhance the appearance of colour of fabric and paper, usually by absorbing light in the ultraviolet and violet region (340-370 nm) of the electromagnetic spectrum, and re-emitting light in the blue region (420-470 nm). Causes a “whitening” effect by increasing the overall amount of blue light reflected. Optically colourless on the substrate and does not absorb in the visible part of the spectrum. Also referred to as a brightening agent; fluorescent whitening agent; optical brightener; or whitener. See closely related: bleaching agent (U024); luminescent agent (U086).

Code: U026
Title: By-products
Description: Substances resulting from the manufacturing process, which can be partially or completely removed from the intended product, mixture or manufactured item and have commercial value on their own or by adding to another product, mixture or manufactured item. See closely related: impurities (U078).

Code: U027
Title: Catalyst
Description: Substance that increases the rate of the intended chemical reaction but is in its original state at the completion of the reaction. See closely related: chemical reaction regulator (U030).

Code: U028
Title: Chain transfer agent
Description: Substance that terminates the growth of a molecular chain and forms a new radical that can act as the initiator for a new chain.

Code: U029
Title: Chelating agent
Description: Substance that has the ability to complex with metallic ions by forming two or more coordinate bonds with a single metal ion. After the first coordinate bond, each successive donor atom that binds creates a ring containing the metal ion; this cyclic structure is called a chelation complex or chelate. Used in wash solutions in regions where water is hard (to bind with calcium or magnesium and soften water). Used to remove ions from solutions or soils by forming a type of coordination complex that can be removed without further interactions. Cleans oxide films from metals by stabilizing metal ions through complexing heterocyclic rings around each ion. Also referred to as a chelant; sequestrant; sequestering agent; complexing agent; chlorine scavenger; or builder.

Code: U030
Title: Chemical reaction regulator
Description: Substance used to change the rate of a chemical reaction, start or stop the reaction, or otherwise influence the course of the reaction. May or may not be consumed or becomes a part of the reaction product. Also referred to as an accelerator; activator; inhibitor; cross linking agent; initiator; enzyme; exotherm modifier; lytic agent; polymer cross linking agent; rubber accelerator activator; retarder; shortstops; or vulcanizing agent. See closely related: catalyst (U027); terminator/blocker (U117).

Code: U031
Title: Cleaning agent
Description: Substance used to remove or breakdown soils, stains, or impurities from surfaces into smaller, more soluble pieces for removal. Examples include: enzymes, other microbial cleaning agents, oxides, sulfides. Not abrasive (U001); chelating agent (U029); anti-scaling agent (U017); foamant (U066); solvent (U111); surfactant (U114); or brightener (U025).

Code: U032
Title: Cloud-point depressant
Description: Substance that depresses the temperature at which solids begin to separate from a liquid at a temperature lower than that normally allowed.

Code: U033
Title: Coalescing agent
Description: Substance used in polymer emulsions that lower minimum film-forming temperature (MFT) and upon evaporation, yields a hard film. Used in polishes, paints and coatings. Examples include: glycol, ether, pyrrolidines, benzoates. Also referred to as a minimum film-forming temperature (MFT) modifier.

Code: U034
Title: Conductive agent
Description: Substance used to conduct electrical current. Also referred to as an electrolyte; or electrode material.

Code: U035
Title: Corrosion inhibitor
Description: Substance used to prevent or retard corrosion on metallic materials. Used in many products packaged in metal containers (such as aerosol products). Used in lubricants and other metal treatment products to provide protection to the substrates or surfaces on which the lubricants are used. Also referred to as a corrosion‑inhibiting additive; rust preventative; anticorrosion agent; or antirust agent.

Code: U036
Title: Crystal growth modifiers (nucleating agents)
Description: Substance used to reduce or increase crystal growth.

Code: U037
Title: Deflocculant
Description: Substance used to fluidize concentrated slurries to reduce their bulk viscosity or stickiness in processing or handling. See closely related: anti-caking agent (U012).

Code: U038
Title: Defoamer
Description: Substance that controls, reduces or prevents foam from forming by disrupting the continuous film of liquid. Often used to improve filtration, dewatering, washing, drainage of suspensions, mixtures, and slurries. Also referred to as an antifoaming agent.

Code: U039
Title: Dehydrating agent (desiccant)
Description: Substance used to absorb and remove water from gases or liquids to induce or maintain a state of dryness. Substances are usually hygroscopic materials. See closely related: drier (U045); adsorbent (U008).

Code: U040
Title: Demulsifier
Description: Substance used to separate an emulsion or prevent its formation.

Code: U041
Title: Density modifier
Description: Substance that modifies the density of a material. Also referred to as density modifying agents. See closely related: viscosity modifier (U122); thickening agent (U118).

Code: U042
Title: Deodorizer
Description: Substance that reduces, eliminates or counteracts unpleasant odour and protects against the formation of malodour. Also referred to as an odour agent; or deodorizing agent. Not fragrance (U067).

Code: U043
Title: Diluent
Description: Substance typically in the form of a liquid that serves primarily to reduce the concentration of the other ingredients in a formulation or to modify the consistency or other properties. The term is most often used for liquid formulations, with the term filler used for solid or powder formulations. Also referred to as a thinner; or mineral spirits. See closely related: solvent (U111). Not filler (U056).

Code: U044
Title: Dispersing agent
Description: Substance added to a suspending medium or suspension; to ensure proper dispersion; to prevent settling or clumping. Examples include: substance used in dispersal of dyes to ensure uniform colouration. Also referred to as an anti-settling agent; dispersant; or suspending agent. Not surfactant (U114).

Code: U045
Title: Drier
Description: Substance that speeds the drying of paint, ink, etc. Often organometallic compounds. Examples include: metal soaps which are used as drying agents that promote the hardening of coatings. Also referred to as a siccative. See closely related: adsorbent (U008); dehydrating agent (U039). Not hardener (U072).

Code: U046
Title: Dust suppressant
Description: Substance used to control finely grained solid particles to reduce their discharge into the air. Also referred to as a dust binding agent.

Code: U047
Title: Dusting agent
Description: Substance that is dusted on to the surface of a material (for example, rubber) to reduce surface tack. Also referred to as a detackifier.

Code: U048
Title: Dye
Description: Substance used to impart colour to other materials or mixtures. Added to a material for colour and generally requires some degree of solubility to allow it to dissolve or disperse in water or diffuse into the polymeric matrix. Molecularly dispersed within a liquid, transferred to a material, and bound to that material through intermolecular forces. Typically, organic substances, although exceptions do exist. Example types: azo, anthraquinone, amino azo, aniline, eosin, stilbene, acid, basic or cationic, reactive, dispersive and natural dyes. Also referred to as a colourant. See closely related: pigment (U094).

Code: U049
Title: Elasticizer
Description: Substance that increases the elasticity of a material. Also referred to as an elasticity modifier.

Code: U050
Title: Embalming agent
Description: Substance used for the preservation of biological tissue. Examples include: embalming fluid, arterial fluid, cavity fluid, surface embalming fluids. See closely related: preservative (U099). Not biocide (U023).

Code: U051
Title: Emulsifier
Description: Substance used to ensure that a thick mixture of oil and water will maintain an even distribution of ingredients that will not separate. Without emulsifiers, the liquid will separate into two parts or phases. Emulsifiers are used to prepare emulsions, such as fabric softeners, creams, lotions and many food products. Emulsifiers have both lipophilic and hydrophilic components. Also referred to as an emulsifying agent. See closely related: surfactant (U114).

Code: U052
Title: Energy releasers (explosives, motive propellant)
Description: Substance characterized by chemical stability, but may be induced to undergo rapid chemical change without an outside source of oxygen, rapidly producing a large quantity of energy and gas accompanied by a large increase in volume and an explosion, bursting, or expansion. Also referred to as a blasting agent; detonator; incendiary; or pyrotechnic.

Code: U053
Title: Etching agent
Description: Substance that removes unprotected areas of metal or glass surfaces via chemical action. Usually acids or bases. Used in processes such as chemical milling; industrial etching; electro etching; photochemical machining; photochemical milling; photo etching; acid etching; vapour phase etching.

Code: U054
Title: Explosion inhibitor
Description: Substance used to reduce the explosion potential of flammable materials.

Code: U055
Title: Fertilizers and supplements (non-pesticidal)
Description: Substance represented for use as a plant nutrient (fertilizer) or for use in the improvement of the physical condition of soils or to aid plant growth or crop yields (supplement). Examples include: phosphates, lime, nitrates, potash compounds, alum, ammonia and ammonia salts, urea, mineral supplements.

Code: U056
Title: Filler
Description: Substance added to fill out a dry product formulation and to lower the concentration of other ingredients. A finely divided substance usually added to extend volume and sometimes to improve desired properties, such as whiteness, consistency, lubricity, density or tensile strength. Used to provide bulk, increase strength, increase hardness, or improve resistance to impact. Used to extend a material and to reduce its cost by minimizing the amount of more expensive substances used in the production of articles. Used to fill cavities or tighten joints. Also referred to as a bulking agent; pigment extender; inert filler; or impact modifier.

Code: U057
Title: Film former
Description: Substance used in forming a thin continuous sheet on its substrate that acts as a barrier against the environment (for example, silicone, polymers). Also referred to as a drying oil.

Code: U058
Title: Fire extinguishing agent
Description: Substance that aids to slow down combustion once started; remove heat faster than it is released; separates the fuel and oxidizing agent; and/or dilutes the vapour phase concentration of the fuel and oxidizing agent below what is needed for combustion.

Code: U059
Title: Fixing agent (mordant)
Description: Substance used to interact with a dye on fibres to improve fastness. Also referred to as a dye transfer inhibitor.

Code: U060
Title: Flame retardants
Description: Substances that alter the normal degradation or combustion processes of plastics, rubbers, textiles, papers, and woods, etc. Used on the surface of or incorporated into combustible materials to reduce or eliminate their tendency to ignite when exposed to heat or a flame for a short period of time. Used to raise the ignition point; and/or to slow down or prevent combustion. Examples include: inorganic salts, chlorinated or brominated organic compounds, organic phosphates/phosphonates.

Code: U061
Title: Flavouring and nutrient
Description: Substances used in food, animal feedstuffs, and some non-food products to produce or alter taste or odour or nutritional value. Used to stimulate taste chemical senses or to enhance nutritional value. Also referred to as a flavouring agent; bittering agent (denaturant); vitamins or minerals. Not active ingredients in health products (U004).

Code: U062
Title: Flocculating agent
Description: Substance that facilitates the coagulation of suspended solids in liquid by enhancing the electrostatic attractive forces between particles. Flocculating agents are principally used to aid in making solid-liquid separations. Also referred to as a coagulant.

Code: U063
Title: Flotation agent
Description: Substance used to concentrate targeted substances or materials on the surface of a liquid mixture for subsequent separation. Used to obtain minerals from ores; to float suspended materials separated from the water column in water clarifiers, to remove ink in deinking processes. Also referred to as flotation oil.

Code: U064
Title: Flow promoter
Description: Substance that reduces drag in fluids in motion and between a fluid and a conduit surface.

Code: U065
Title: Flux agent
Description: Substance used to promote the fusing of minerals or prevent oxide formation. Used for casting or joining materials. Also referred to as a welding agent; or soldering agent.

Code: U066
Title: Foamant
Description: Substance that promotes or enhances formation of a lather or foam (for example a dispersion of a gas in a liquid or solid). Used to form physically, by expansion of compressed gases or vaporization of liquid, or chemically, by decomposition evolving a gas, a foam or cellular structure in a plastic or rubber material. Also referred to as a foaming agent; expanding agent; frother; or foam booster.

Code: U067
Title: Fragrance
Description: Substance used to impart pleasing odours. Fragrance compounds are molecules that stimulate the human olfactory chemical senses. Also referred to as musk. Not deodorizer (U042).

Code: U068
Title: Freeze-thaw additive
Description: Substance used in synthetic resin emulsions or synthetic lattices to enable paints, coatings, and other products to retain original consistency and to resist coagulation when exposed to freezing and thawing prior to application.

Code: U069
Title: Fuel
Description: Substance used to create mechanical or thermal energy through chemical reactions. Used to evolve energy in a controlled combustion reaction. Examples include: coal, oil, gasoline, various grades of diesel fuel.

Code: U070
Title: Fuel additives
Description: Substances added to a fuel for the purpose of improving combustion or limiting the production of undesirable combustion products. Examples include: combustion accelerators, cetane improvers, antiknock agents. Not corrosion inhibitor (U035); or lubricating agent (U085).

Code: U071
Title: Gelling modifier
Description: Substance that influences the formation or destruction of a gel.

Code: U072
Title: Hardener
Description: Substance used to increase the strength, hardness, and abrasion resistance of coatings, adhesives, sealants, elastomers, and other products. Also referred to as a curative; or curing agent. Not sealant - barrier (U105).

Code: U073
Title: Heat stabilizer
Description: Substance that protects substrates such as polymers from degrading effects of heat by chemically stabilizing the substrate during heat induced degradation (such as erosion, melting, vaporization or oxidation).

Code: U074
Title: Heat transferring agent
Description: Substance used to transmit or to absorb heat from another material. Examples include: cooling agent, heating agent, surface cooling agent, coolants.

Code: U075
Title: Humectant
Description: Substance used to retard moisture loss from the product during use. Also used in self-care and other products with skin exposure to prevent loss of moisture from the skin and retain natural moisture.

Code: U076
Title: Hydraulic fluids
Description: Substance, typically liquid or gaseous, used for transmitting pressure and to transfer power in hydraulic machinery. Also referred to as a pressure transfer agent. Examples include: hydraulic/transmission fluid, brake fluid, power steering fluid, fluid shock absorbers.

Code: U077
Title: Impregnation agent
Description: Substance used to admix with solid materials, which retain their original form, and which penetrate into a substrate to provide specific properties. Also referred to as an entrainment aid.

Code: U078
Title: Impurities
Description: Substances naturally present in a reactant or substances that are produced as a result of the manufacturing process and has no beneficial properties in the final product, mixture or manufactured item. Also referred to as a contaminant. See closely related: by-products (U026).

Code: U079
Title: Incandescent agent
Description: Substance that is used to emit light at high temperature.

Code: U080
Title: Insulators
Description: Substance used to prevent or inhibit the transmission of heat, electrical current, light, or sound between two media. Acoustic, electrical, or thermal insulators. Examples include: dielectric fluid, electric resistant materials, encapsulant.

Code: U081
Title: Intermediate
Description: Substance consumed in a reaction in order to manufacture other chemical substances at an industrial processing facility. Formed (directly or indirectly) from reactants and reacted further to create (either directly or indirectly) the products of a chemical reaction.

Code: U082
Title: Ion exchange agent
Description: Substance, usually in the form of a solid matrix, used to selectively remove targeted ions from a solution by adsorbing ions of a given charge (either cations or anions) in solution and replacing/releasing equivalent quantities of other ions of the same charge into the solution. Examples generally consist of an inert hydrophobic matrix such as styrene-divinylbenzene or phenol-formaldehyde, cross-linking polymer such as divinylbenzene, ionic functional groups including sulfonic, carboxylic or phosphonic acids.

Code: U083
Title: Laboratory substances
Description: Substances used in a laboratory for chemical analysis, chemical synthesis, extracting and purifying other chemicals, dissolving other substances, and similar activities. Examples include: substances that change colour to indicate pH, redox potential or other endpoints, halogenated and non-halogenated solvents, substances used in titrations and chromatography, Grignard reagents used in organic synthesis, laboratory reagents, inorganic acids and bases.

Code: U084
Title: Leaching agent
Description: Substance that, when added to a solvent, aids in the dissolution of a component of an insoluble solid mixture. Used to extract certain components from the solid phase into the liquid phase. See closely related: solubility enhancer (U110).

Code: U085
Title: Lubricating agent
Description: Substance introduced between two moving surfaces or adjacent stationary surfaces to reduce the friction between them, improve efficiency, reduce wear, and reduce heat generation. Enhances the lubricity of other substances to shear easily by minimizing contact between the surfaces so that the frictional force is low.

Code: U086
Title: Luminescent agent
Description: Substance that emits visible radiation as a direct consequence of the absorption of photons, charged particles, or chemical (for example, UV light) and that ceases to emit radiation when the stimulating radiation is discontinued. Also referred to as a fluorescent agent. See closely related: brightener (U025).

Code: U087
Title: Magnetic element
Description: Substance added into materials to make them magnetic.

Code: U088
Title: Monomers
Description: Substance usually containing carbon and of a low molecular weight and simple structure which is capable of conversion to polymers, synthetic resins, or elastomers by repetitive combination with itself or other similar molecules.

Code: U089
Title: Opacifier
Description: Substance that renders solutions opaque; reduces transparency or the ability of light to pass through solution; added to finished products to reduce their clear or transparent appearance without imparting colour.

Code: U090
Title: Oxidizing agent
Description: Substance that gains/accepts electrons (becomes reduced) during their reaction with a given reagent (for example, reducing agent). Oxidizing agents commonly contribute oxygen to other substances. Also referred to as an oxidant. Examples include: nitric acid, perchlorates, hexavalent chromium compounds, peroxydisulfuric acid salts.

Code: U091
Title: Pest control substances
Description: Substance or mixture of substances used as an ingredient or formulant in pest control. Not biocide (U023).

Code: U092
Title: pH regulating agent
Description: Substance used to alter, stabilize, or control the pH (hydrogen ion concentration) within a desired range. Also referred to as a buffering agent; pH adjuster; pH regulating agent; or neutralizing agent.

Code: U093
Title: Photosensitizers
Description: Substance that absorbs electromagnetic radiation and transfers energy to other materials making them susceptible to chemical change. Examples include: activation of photographic emulsions, photoresist.

Code: U094
Title: Pigment
Description: Substance, usually in the form of a dry powder and with a positive colourant value, that imparts colour to another substance or mixture through binding or adhesion. May contribute towards opacity, durability, or corrosion resistance and may scatter or absorb light. Larger than molecular particle size and held in place by corresponding low mobility. Pigments differ from dyes in that they are insoluble in the vehicle and exist as dispersed compounds in paint rather than as a solute. See closely related: dye (U048).

Code: U095
Title: Plasticizer, specific to polymers
Description: Substance that softens polymers. Added to a high polymer to facilitate processing and to increase flexibility, plasticity, fluidity or toughness of the final product by internal modification (solution) of the polymer molecule. May be added internally or externally. A rigid polymer can also be externally plasticized by addition of a plasticizer, which imparts the desired flexibility but is not chemically changed by reaction with the polymer. See closely related: plasticizer, not otherwise specified (U096).

Code: U096
Title: Plasticizer, not otherwise specified
Description: Substance that softens cement, concrete, wallboard, clay bodies or materials other than polymers. Added to materials to facilitate processing and to increase flexibility, plasticity, fluidity or toughness of the final product by internal modification (solution) of the molecule. May be added internally or externally. See closely related: plasticizer, specific to polymers (U095).

Code: U097
Title: Plating agent
Description: Substance used as a source of metal or inorganic compound that is deposited on another surface or that aids in such a deposition. Used in processes such as electroplating; galvanization; coating; phosphate treatment; chromate treatment; black oxide coating; anodic oxidation; diffusion treatment; carburizing; nitriding; or carbon nitriding. Also referred to as an electroplating agent; galvanization agent; or coating agent.

Code: U098
Title: Polymerization promoter
Description: Substance that enables a reaction between two or more dissimilar polymers, allowing them to become more intimately mixed than before. Also referred to as a compatibilizer.

Code: U099
Title: Preservative
Description: Substance used to eliminate or minimize the build-up of microbial growth to protect against decay, decomposition discolouration or spoilage and maintain product performance over full shelf-life. Examples include: food preservative, wood preservative, cosmetic preservative, drug preservative. Not for preservation of biological tissues; see closely related: embalming agent (U050). Not biocide (U023); or pest control substances (U091).

Code: U100
Title: Processing aid, not otherwise specified
Description: Substance used in applications other than the production of oil, gas, or geothermal energy to control foaming, corrosion, alkalinity or pH, or to improve the operation of processing equipment. Not processing aid, specific to petroleum (U101).

Code: U101
Title: Processing aid, specific to petroleum production
Description: Substance added to water, oil, or synthetic fluids or other drilling extraction and processing fluids to control foaming, corrosion, alkalinity and pH, microbiological growth or hydrate formation, or used to improve the operation of equipment during drilling, extraction and processing of oil, gas, and other products or mixtures from beneath the earth's surface. Examples include: components of hydraulic fracturing fluids (including proppants), weighting agents added to drilling fluids to increase their density, octal alcohol added to prevent foaming, production substances and substances added to inhibit the formation of hydrates of natural gas and water. 

Code: U102
Title: Propellants, non-motive (blowing agents)
Description: Substance that is used for expelling products from pressurized containers. Used to dissolve or suspend other substances and either to expel those substances from a container in the form of an aerosol or to impart a cellular structure. Provides the force necessary to expel the contents of aerosol containers upon discharge of the internal pressure through expansion of the liquefied or compressed gas. The formulated product in the pressurized container may be in solution, emulsion, or suspension.

Code: U103
Title: Reducing agent
Description: Substance that loses/donates electrons (becomes oxidized) during reactions with a given reagent (for example, oxidizing agents). Also referred to as a reductant. Examples include: hydrazine, sodium thiosulfate, coke produced from coal.

Code: U104
Title: Refrigerant
Description: Substance in working fluids used in closed systems that function as a heat carrier or heat transfer agent. Typically used within machines such as air conditioning units, refrigerators, or walk-in freezers to cool enclosed air and reduce temperatures.

Code: U105
Title: Sealant (barrier)
Description: Substance used to fill up a space (for example, joints, gaps or cavities between two substrates) and prevent seepage of moisture or air. Examples include: mastic sealant, caulk/caulking. Not hardener (U072).

Code: U106
Title: Semiconductor and photovoltaic agent
Description: Substance that has resistivity between that of insulators and metals. Usually changeable by light, heat or electrical or magnetic field. Generates electromotive force upon the incidence of radiant energy. Used in manufacturing of electrical components and electronic devices such as transistors and diodes. Examples include: semiconductor materials, liquid crystal materials.

Code: U107
Title: Sizing agent
Description: Substance applied to substrates such as fabric, yarn, paper products, or plaster to increase abrasive resistance, stiffness, strength, smoothness, or reduce absorption.

Code: U108
Title: Softener
Description: Substance used for softening materials to improve feel, to facilitate finishing process, or to impart flexibility or workability; used in textile finishing to impart superior “hand” to the fabric and facilitate mechanical processing; has the capability of imparting softness and pliability to washable textile fabrics. Examples include: fabric softener, fabric conditioner, conditioning agent, moisturizer.

Code: U109
Title: Solids separation (precipitating) agent, not otherwise specified
Description: Substance used to promote the separation of suspended solids from a liquid. Examples include: dewatering aids, drainage aids. Not flocculating agent (U062); or flotation agent (U063).

Code: U110
Title: Solubility enhancer
Description: Substance that prevents chemicals or materials from separating or falling out of solution and increases the concentration of the solute in the concentrated solution. Often used in concentrated formulations. See closely related: leaching agent (U084).

Code: U111
Title: Solvent
Description: Substance primarily used to dissolve another substance (solute) to form a uniformly dispersed mixture (solution) at the molecular or ionic size level; to suspend solid particles or colloidal materials to yield suspensions or gels, to provide dissolving capability required for a stable formulation; to dissolve certain components of the formulation to aid dispersion of components; to aid in oil cleansing power and control film drying rate; to solubilize soils on surfaces and facilitate removal. Used to dissolve, disperse, or extract. Also referred to as a vehicle. See closely related: diluent (U043).

Code: U112
Title: Stabilizing agent
Description: Substance that tends to keep a compound, solution, or mixture from changing its form or chemical nature. Renders or maintains a solution, mixture, suspension, or state resistant to chemical change. Used to prevent or slow down spontaneous changes in or aging of materials.

Code: U113
Title: Surface modifier
Description: Substance that may be added to other ingredients to adjust the optical properties associated with the surface of a material such as affect the lustre, increase gloss, or alter the reflectance exhibited by a surface. Also referred to as a polishing agent; refractive index modifier; surface coating agent; flatting agent; or gloss agent.

Code: U114
Title: Surfactant
Description: Substance which, when added to water, has surface active properties and is capable of reducing the surface tension of the water promoting the penetration of or spread over the surface of another material and reducing interfacial tension between two liquids, between a liquid and a solid, or between liquid and air. Also referred to as a surface active agent. Closely related: emulsifier (U051), wetting agent (non-aqueous) (U125).

Code: U115
Title: Swelling agent
Description: Substance added to a material to cause that material to increase in volume and become softer.

Code: U116
Title: Tanning agents
Description: Substances used for treating or pre-treating leather materials such as hides and skins and not covered by other substance function codes. Examples include: leather oils, defatting agents, fat liquoring agents, de-liming agents.

Code: U117
Title: Terminator/blocker
Description: Substance that reacts with the end of a growing polymer chain, stopping further polymerization (terminator) or a substance used to protect a reactive moiety on a precursor during organic synthesis of a product that is subsequently removed regenerating the reactive moiety (blocker). See closely related: chemical reaction regulator (U030).

Code: U118
Title: Thickening agent
Description: Substances, typically hydrophilic, used to form solid or semisolid dispersions of a mixture or increase the viscosity of liquid mixtures and solutions and to aid in maintaining stability by their emulsifying properties without changing their other properties. Four classifications are recognized: 1) Starches, gums, casein, gelatine and phycocolloids; 2) semisynthetic cellulose derivatives (for example carboxymethyl-cellulose); 3) polyvinyl alcohol and carboxy-vinylates (synthetic); and 4) bentonite, silicates, and colloidal silica. May also be hydrophobic at lower temperatures. Also referred to as a thickener; rheology modifier; or viscosity index improver. See closely related: density modifier (U041); viscosity modifier (U122).

Code: U119
Title: Tracer
Description: Substance that possesses a readily detectable radioactive/isotopic label or chemical moiety which is added to biological/environmental media or chemical reactions to elucidate the transformation/transportation processes that are occurring.

Code: U120
Title: UV stabilizer
Description: Substance that protects the product from chemical or physical deterioration induced by ultraviolet light. Absorbs UV radiation, thereby protecting products including varnishes, pigments, or certain polymers against UV degradation. Also referred to as a UV absorber; or light stabilizer.

Code: U121
Title: Vapour pressure modifier
Description: Substance added to a liquid to modify its vapour pressure.

Code: U122
Title: Viscosity modifier
Description: Chemical substance used to alter the viscosity of another substance. Used to decrease or increase the viscosity of finished products; to modify the flow characteristics of other substances, or mixtures to which they are added; to control the deformation or flow ability of a wax product. Also referred to as a viscosity adjuster; or viscosity controlling agent. See closely related: density modifier (U041); thickening agent (U118).

Code: U123
Title: Wastes
Description: Substances that are removed from the final product, mixture or manufactured item during the manufacturing process and currently have no commercial value nor value as a recycled agent.

Code: U124
Title: Waterproofing agent
Description: Substance that lowers the surface energy to protect surfaces against water by forming water beads. Also referred to as a water-beading agent.

Code: U125
Title: Wetting agent (non-aqueous)
Description: Substance that promotes coating of an organic liquid on a solid material by lowering the surface tension. Note, the substance is not added to water. Wetting agents that are added to water (aqueous wetting agents) are covered under the Surfactant code (U114).

Code: U126
Title: Wrinkle resisting agent
Description: Substance used to impart wrinkle-resistance in textiles, paper or leather.

Code: U127
Title: X-Ray absorber
Description: Substance used to block or attenuate X-rays.

Code: U999
Title: Other (specify)
Description: Substances contained in mixture, products or manufactured items intended for consumer, commercial, or industrial use that are not covered within any other substance function code. Specify the function.