An insecticide based on 1,2,3,4,10,10-hexachloro-1,4,4a,5,8,8a-hexahydro,endo,exo-1,4:5,8-dimethanonaphthalene. It degrades into the substance dieldrin in the body and the environment. It was used in crops like corn and cotton and is now classified as a Persistent Organic Pollutant (POP).

Under the Stockholm Convention on Persistent Organic Pollutants, use of this chemical in Europe is subject to restriction.


Adsorbable Organic Halogens is a measurement often used in waste water testing to indicate the overall level of the halogens, fluorine, chlorine, bromine and iodine.

This “sum parameter” comes from a standard analytical procedure, which gives no information on the source or nature of halogens present nor on their toxicity. It has the advantage of being simple to measure; alternative methods of measuring levels of individual compounds are complex and require costly equipment.


The Barcelona Commission, the objective of which is the protection of the Mediterranean Sea against pollution.


Best Available Techniques: BAT standards are used to judge the performance of industrial processes and to provide a target for improvement plans. They are gathered in a BAT Reference Document (BREF).


Bioconcentration Factor: ratio between the concentration in an organism and the concentration in an environmental compartment.


Best Environmental Practice: the application of the most appropriate combination of environmental control measures or strategies in order to reduce the impact of specific substances or applications.


Bioaccumulation is the accumulation of a substance in a living organism as a result of its intake from food and the environment. It is extremely important in the risk analysis of a chemical.


Accumulation of a substance in an organism by absorption from the environment irrespective of any intake with food. The concept is of particular importance for aquatic life with regard to the absorption of those fat-soluble substances which are only broken down slowly.


This term denotes the accumulation of substances in a living organism from food intake. Simple organisms such as algae can absorb minute quantities of a substance which are transferred through the food chain to higher levels such as fish and preditory birds. Biomagnification along a food chain will result in the highest concentrations of a substance being found at the top of the food chain.


Bleach is produced by reacting chlorine with a dilute sodium hydroxide solution to give sodium hypochlorite. Bleach is used for disinfection, water purification, cleaning and for whitening paper, soap, straw and cotton.


BAT Reference Document (See BAT: Best available Technique).


Carbon tetrachloride is produced by the high temperature chlorination of propylene or methane. It is used as a feedstock in the production of CFCs, HCFCs and HFCs, as a process agent in the production of chlorine, to extract nitrogen trichloride, and as a solvent to recover chlorine from tail gas. It has been phased out in dispersive uses since 1995 under the Montreal Protocol.

Read more about this substance on the European Chlorinated Solvents Association website


The European Chemical Industry Council (Cefic) is the Brussels-based organisation representing national chemical industry federations and chemical companies.


An insecticide based on 1,2,4,5,6,7,8,8-octachloro-2,3,3a,4,7,7a-hexahydro-4,7-methano-indene. It was used as a pesticide on crops like corn and citrus and on home lawns and gardens and it is now classified as a POP .

Under the Stockholm Convention on Persistent Organic Compounds, use of this chemical in Europe is subject to restrictions.


Collective term for chlorinated derivatives of benzene, toluene, phenol, naphthalene and bi-phenyl and other compounds containing at least one benzene ring. Chlorinated aromatics are widely used as intermediates in the manufacture of medicines, agricultural chemicals and paints.


See Organic Chlorine Compounds


Chlorinated paraffins are chemicals manufactured by chlorination of liquid n-paraffin or paraffin wax. The largest application for chlorinated paraffins is as a plasticiser and flame-retardant in flexible PVC. They are also used as plasticisers in paint, sealants and adhesives.

Higher chlorine content grades are used as flame-retardants in a wide range of rubbers and polymer systems.

Another major outlet for chlorinated paraffins is in the formulation of metalworking lubricants where they have long been recognised as one of the most effective additives that can be used in a wide range of engineering areas.



Trichloroethylene, tetrachloroethylene (also known as perchloroethylene), and methylene chloride (also known as dichloromethane) are the main solvents in this group. Due to their non-flammability, these compounds have been widely used for cleaning metals in the electronics industry and for dry cleaning of clothes. The use of 1,1,1-trichloroethane was phased out at the end of 1995 under the Montreal Protocol.

The chemical industry sponsors research on chlorinated solvents. It also participates actively in the preparation of guidelines for safe handling, working closely with its customers. The industry has also developed recycling schemes through which its customers can return spent solvent for recovery and re-use whilst final wastes are incinerated. The decline in consumption of virgin chlorinated solvents in recent years is due to a combination of increased use of recycled product, reduced emissions to the atmosphere and other conservation techniques. Euro Chlor has fully supported this process.


1. Introduction of chlorine into a chemical compound.
2. Sterilisation of drinking and swimming pool water or oxidation of undesirable impurities, using chlorine or its compounds.
3. Exposure of wool to chlorine solutions to prevent unwanted felting.


In its “normal” state, chlorine is a greenish yellow gas, but at -34°C it turns to a liquid. It is the eleventh most common element in the earth’s crust and is widespread in nature.

Chlorine is a key building block of modern chemistry and can be used directly (e.g. to disinfect water); as a raw material for chlorine-containing products (e.g. plastics, pharmaceuticals, pesticides) and as an intermediate to manufacture non-chlorinated products (e.g. polycarbonates and polyurethanes).



Important intermediates in the production of pharmaceuticals, perfumes, agricultural chemicals and paints. Chlorobenzenes are produced by the chlorination of benzene.


See vinyl chloride monomer (VCM).


A hydrocarbon in which some or all of the hydrogen atoms have been replaced by chlorine and fluorine. Fluorocarbons are used as a feedstock, as a refrigerant, as a solvent and as a blowing agent for plastic foam.


Chloroform, which is produced mainly by the chlorination of methane, is used as an intermediate in the production of refrigerants, agrochemicals and fluoropolymers. It is no longer used as an anaesthetic.


International Committee of Textile Care. Dry-cleaning is a major application of perchloroethylene.

See the perchloroethylene page on the website of the European Chorinated Solve,ts Association ECSA.

More information on


Chemicals classified as carcinogenic, mutagenic or reprotoxic (i.e. they can impact reproduction).


Dichloro-diphenyl-trichloroethane, a potent insecticide now only used for the prevention of malaria in specific regions of the world when approved by the World Health Organization (WHO). It is classified as a POP. Under the Stockholm Convention on Persistent Organic Pollutants, use of this chemical in Europe is subject to restriction.


Formerly a pesticide for crops like corn and cotton, based on 1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4,4a,5,6,7,8,8a-octahydro,endo,exo-1,4:5,8-dimethanonaphthalene. It is now classified as a POP. Under the Stockholm Convention on Persistent Organic Pollutants, use of this chemical in Europe is subject to restriction.



Dioxin is a generic term for a group of more than 200 complex compounds, all of which contain chlorine (specialist name: polychlorinated dibenzodioxins and furans, PCDDs and PCDFs). Seventeen of the compounds in this group have been found to be toxic to varying extents. Their impact on living organisms varies greatly from one animal species to another.

Dioxins in trace quantities are created naturally (e.g. by volcanoes) and as unintentional by-products in numerous combustion processes (e.g. forest fires, cigarettes, bonfires, car engines etc.), in metal smelting and recycling processes. Only a small proportion comes from the chemical industry.


The study of the harmful effects of chemical compounds on species, population and the natural environment.


European Chlorinated Solvent Association, the sector group of Euro Chlor dealing with chlorinated solvents.


European inventory of existing commercial chemical substances


The process in which an electric current flowing through a water solution of a chemical breaks that compound up into its component parts.

Chlor-alkali is produced by electrolysis of brine (salt dissolved in water).


Endrin is a solid, white, almost odourless substance that was used as a pesticide to control insects, rodents, and birds. It is based on 1,2,3,4,10,10-hexachloro-6,7-epoxy-1,4,4a,5,6,7,8,8a-octahydro-,endo,endo-1,4:5,8-dimethanonaphthalene; it is classified as a POP. Under the Stockholm Convention on Persistent Organic Pollutants, use of this chemical in Europe is subject to restriction.


Polychlorinated dibenzofurans (PCDFs), often associated with dioxins (PCDDs), are not industrially produced as such but found as impurities in some heavy chlorinated chemicals and as by-products of combustion (from wastes, coal, petroleum products, wood….).


A family of chemical elements that comprises astatine, fluorine, chlorine, bromine and iodine.


Hydrochloric acid or hydrogen chloride, a colourless gas with a pungent odour; its aqueous solution is known as hydrochloric acid. Hydrogen chloride is produced by burning hydrogen and chlorine together and is also a by-product of the chlorination of organic compounds.

HCl is used in the production of the plastic PVC, ferric chloride (needed for waste water purification) and silicones.


The Helsinki Commission, which has the objective of protecting the Baltic Sea against pollution.

More information about the Helsinki Commission on


A fungicide based on 1,4,5,6,7,8,8-heptachloro-3a,4,7,7a-tetrahydro-4,7-methano-indene. It is a white powder that smells like camphor, and it was used extensively in the past for killing insects in homes, buildings, and on food crops, especially corn. It is now classified as a POP.

Under the Stockholm Convention on Persistent Organic Compounds, use of this chemical in Europe is subject to restrictions.

More information about POPS on


International uniform chemical information database, a software application to capture, store, maintain and exchange data on intrinsic and hazard properties of chemical substances


Mercury is a naturally-occurring element which is present in various ores. The major mined source in Europe has been in Spain (Almadén). Mercury has been used for 100 years in electrolytic chlorine production, is gradually being phased out in favour of membrane technology.

Voluntary conversion of all mercury cells was to be expected to have been completed by 2020, but recent (2014) European regulation now stipulates that the use of mercury based technology must be phased out before December 2017.


Methylene chloride (dichloromethane), a versatile chlorinated solvent, is produced by chlorination of either methane or methyl chloride. It is used in a broad spectrum of applications: paint stripping, adhesives, aerosols, process solvent and tablet-coating agent in the pharmaceutical industry, solvent in polycarbonate production, blowing agent for polyurethanes, food extraction, cold degreasing of metals, printing, gauze coating, fabric coating, etc. See other information and comments under “Chlorinated Solvents” .

See the chlorinated solvent page


Chlorine is one of the elements most frequently found in nature; it is even more abundant than carbon. Chlorides, i.e. salts containing chlorine, are one of the few raw materials which will not be exhausted within the foreseeable future. Naturally-occurring chlorine compounds are present in our blood, skin and teeth, and chlorine in the form of hydrochloric acid has an important part to play in the digestive process.

There are also organic compounds present in nature which contain chlorine; marine algae, for example, produce about 5,000,000 tonnes of methyl chloride annually (ie: around 15 times more than yearly industrial production). In total, more than 2,000 natural organic chlorine compounds have already been identified.


Occupational Exposure Limit: General term for concentration of air contaminants above which people should not be exposed at work.


Organic chlorine compounds constitute a group of more than 2,000 substances which are based on organic compounds (i.e. carbon-containing) with one or more chlorine atoms.

The exceptional reactivity of chlorine enables it to be introduced into virtually all basic substances in organic chemistry. It is also very easy to trace, even in minute quantities. A large number of different products with a wide range of chemical and physical properties can be produced by selecting suitable reaction conditions.

Organic chlorine compounds are important synthetic building blocks in the chemical industry, and they are also formed in nature in large quantities.


Organohalogen compounds is the collective term used for compounds containing, in addition to carbon, elements of the halogen group, including astatine, fluorine, chlorine, bromine and iodine. Organochlorine compounds form a sub-group of the organohalogen group.


The Oslo and Paris Commissions, which have the objective of protecting the Northeast Atlantic against pollution. Member countries range from Finland to Portugal and Iceland.


Chemicals classified as persistent, bioaccumulative and toxic


PCBs form a group of compounds which were developed in the 1930s and were mainly used in the electricity supply industry and mining. Due to their accumulation in the food chain, production of PCBs was halted world-wide at the beginning of the 1980s and in 1996 an EC Directive was agreed requiring a phase-out of continuing uses (mainly in ageing electrical equipment). PCBs are, however, still found in trace concentrations in the sea and in the fatty tissue of marine animals.


Customary abbreviations for polychlorinated dibenzo-p-dioxins and dibenzofurans referring to the dioxins and their ‘brother compounds’ furans.
Download and download the easy-to-understand Information Sheet on dioxins.


Perchloroethylene or tetrachloroethylene is the primary solvent used in the industrial and commercial dry-cleaning of clothes. Its other major uses are as a metal cleaning and degreasing solvent, and as a chemical intermediate in the production of several fluorinated compounds.

See the perchloroethylene page


Stability of chemical compounds in the environment. Persistence is an important negative criterion in the ecological assessment of chemicals.


A family of chemicals, produced from phthalic anhydride and alcohols, frequently used as plasticisers to give flexibility to PVC.


A plasticiser is a substance which when added to a material, usually a plastic but also a paint or an adhesive, makes it flexible, resilient and easier to handle. Modern plasticisers are manmade organic chemicals; the majority of which are esters, such as adipates and phthalates. They are major components that determine the physical properties of polymer products. There are more than 300 different types of plasticisers, including chlorinated paraffins.

See the chlorinated paraffins page


Persistent organic pollutant, a group of PBTs which are also capable of long-range transport and deposition; they are believed to be transported primarily in the atmosphere. These have global effects. Most are already banned in Western Europe but some are still in use in developing countries. The POPs include the following 12: PCBs, dioxins and furans, chlorine, aldrin (see higher), dieldrin, DDT , endrin , chlordane , hexachlorobenzene, Mirex , toxaphene and heptachlor. They fall into three groups: chlorinated pesticides; industrial chemicals; and emissions and by-products. POPs are being examined by various national, regional and international bodies with the aim of developing management strategies.



Polyvinyl chloride, a polymer of vinyl chloride used to make a diverse range of cost-effective products with various levels of technical performance suited to a wide range of applications. Many of these PVC products are used everyday and include everything from medical devices such as medical tubing and blood bags, to footwear, electrical cable, packaging, stationery, toys and window frames, roller shutters, water pipes and floor coverings.

Discover much more information about PVC on .


Registration, Evaluation and Authorisation of Chemicals: the EU chemicals policy. It is expected to require companies that manufacture or import more than one tonne of a chemical per year to register it in a central database managed by the EU chemicals Agency. The policy is described in the EU White Paper “Strategy for a future Chemicals Policy”.

See the Reach pages


Development of an allergic reaction, especially involving the skin or lungs when exposed to a chemical.



A solvent is a liquid that has the ability to dissolve, suspend or extract other materials, without chemical change to the material or solvent. Solvents make it possible to process, apply, clean or separate materials. Water is an inorganic solvent. Organic solvents include hydrocarbon solvents, oxygenated solvents and chlorinated solvents.

See the chlorinated solvents page


Chemical name of perchloroethylene (see under that name).

Also see the chlorinated solvents page


Trichloroethylene is mainly used in the degreasing of metals. Under the VOC Directive, its use in that application is restricted to enclosed systems in all new installations; old installations will have to comply with stringent emission limits after April 2007. Trichloroethylene also is used to a much lesser extent in adhesive and aerosol formulations and as a chemical process intermediate in polyvinyl chloride (PVC) and fluorochemical production.

See the chlorinated solvents page


United Nations Economic Commission for Europe: Mission: “To strive to foster sustainable economic growth among its 55 member countries. To that end UNECE provides a forum for communication among States; brokers international legal instruments addressing trade, transport and the environment; and supplies statistics and economic and environmental analysis”.

More information about United Nations Economic Commission for Europe on


United Nations Environment Programme: Mission: “To provide leadership and encourage partnership in caring for the environment by inspiring, informing, and enabling nations and peoples to improve their quality of life without compromising that of future generations.”

More information about United Nations Environment Programme on


Vinyl chloride monomer or chloroethylene, a colourless, flammable gas, used principally in making PVC (polyvinylchloride), an important synthetic resin (plastic).


World Health Organization: the United Nations specialised agency for health. Its objective is “the attainment by all peoples of the highest possible levels of health.”

More information about World Health Organization