Name PRTR	Chlorine and inorganic compounds (as HCl)
CAS no	7782-50-5 (chlorine)
Molecular formula	Cl2 (chlorine)

 Chlorine is a non-metallic element belonging to the group halogens. At room temperature, chlorine is a poisonous, oxidising and corrosive gas. The gas has a yellow-green colour, a sharp, stifling odour and is heavier than air^1,2.

Uses

Chlorine is extracted from sodium chloride salt (NaCl) by electrolysis. Chlorine gas is used in production of vinyl chloride monomers (VCM), which, in turn, is a component of polyvinylchloride (PVC)³. Chlorine is also used within the chemical industry, mainly for production of organic chemicals and hydrochloric acid.

Chlorine gas combined with water vapour form hydrogen chloride, HCl, which is poisonous and corrosive. Hydrogen chloride in water solution (hydrochloric acid) is for example used in metal processing, water treatment and for pH adjustment⁴.

Chlorine is also used as a disinfectant in for example drinking water (sodium hypochlorite) and swimming pools (calcium hypochlorite)⁵. Chlorine is also used as a preservative⁶.

An earlier common use of chlorine gas was as bleaching chemical for chemical pulp and textiles. Within the pulp and paper industry, only bleaching with chlorine dioxide is currently used (ECF – Elementary Chlorine Free), a method that is more environmentally friendly⁷.

Sources and transportation pathways

Pure chlorine exists in nature as chlorine gas (Cl₂). The most important transportation pathway of chlorine and inorganic chlorine compounds (as HCl) is by air. The largest emission sources in Sweden today are operations within the metal industry, the pulp and paper industry, the mineral industry and the energy sector.

Effects on environment and health

Effects on the environment and health vary somewhat between different inorganic chlorine compounds. Chlorine gas is very poisonous to aquatic organisms⁸.

For humans, chlorine gas is poisonous when inhaled and may cause respiratory tract irritation⁹. Chlorine gas also irritates the skin and may cause severe eye irritation. Hydrogen chloride is poisonous when inhaled and may cause severe corrosive damage to the skin and eyes¹⁰.

International agreements and regulations

Chlorine and inorganic chlorine compounds are regulated by the EU Water Framework Directive (2000/60/EC). The UN Protocol on PRTRs and the EU E-PRTR regulation regulate how data on emissions of chlorine and inorganic chlorine compounds is made available.

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¹ https://rib.msb.se/Portal/Template/Pages/Kemi/Substance.aspx?id=456&q=klor&p=1
² https://www.atsdr.cdc.gov/substances/toxsubstance.asp?toxid=36
³ http://www.inovyn.se/142-Produktionsprocessen.htm
⁴ http://www.inovyn.se/142-Produktionsprocessen.htm
⁵ http://periodiskasystemet.nu/klor.html
⁶ https://rib.msb.se/Portal/Template/Pages/Kemi/Substance.aspx?id=456&q=klor&p=1
⁷http://www.skogssverige.se/papper/fakta-om-papper-och-massa/massa-och-papperstillverkning/blekning-av-kemisk-massa 
⁸ https://echa.europa.eu/information-on-chemicals/cl-inventory-database/-/discli/details/76663
⁹ https://echa.europa.eu/information-on-chemicals/cl-inventory-database/-/discli/details/76663
¹⁰ https://echa.europa.eu/information-on-chemicals/cl-inventory-database/-/discli/details/105223