Hazards and risks for human and the environment of chlorine and sodium hypochlorite: no need for further risk reduction measures according to EU report.

 These risk assessments made by the EU authorities were published in December 2007 and are available on :




(summarized by GreenFacts)

Both for human health or the environment, the overall conclusion of the risk assessments on chlorine and sodium hypochlorite published by the Joint Research Centre (JRC) of the European Union was that there is no need for further information and/or testing and no need for risk reduction measures beyond those which are being applied already. Chlorine do not fullfill the PTB (Persistant Toxic and Bioaccumulative substances) criteria.

Human health

Either for workers, humans exposed via the environment, combined exposure or consumers exposure (including household products drinking water, adults or children of 1 year old in swimming pools),  the risk assessment concludes that  there is at present no need for further information and/or testing and no need for risk reduction measures beyond those which are being applied already.

The human population may be exposed to chlorine at the workplace (during manufacturing and use of chlorine as chemical intermediate), use in water disinfection, and indirectly via the environment. For occupational exposure, the relevant route of exposure is inhalation. Human exposure to chlorine gas may lead to local effects on the upper respiratory tract due to the corrosive effects of chlorine.

Measured levels of chlorine in chlor-alkali manufacturing plants and in plants using chlorine as chemical intermediate are in most cases lower than the occupational exposure limit for chlorine. Therefore, the typical average concentrations are  generally far below this limit (0.5 ppm (1.5 mg/m3).

In specific cases in which measured concentrations can be higher than the limit (i.e. during maintenance), adequate protection equipments are worn and strict safety procedures are applied.

Chlorine is of no concern to workers with regard to mutagenicity and carcinogenicity.

There is no direct consumer use of chlorine and consequently no direct public exposure is expected. When chlorine is used for disinfection purposed (in swimming pools and in drinking water treatment), it is added to water and is transformed into hypochlorite and hypochlorous acid.

The possible consumer exposure to these chemicals has been evaluated in sodium hypochlorite Risk Assessment and it has been concluded that no risk is expected.


The conclusions to the risk assessment for chlorine in the aquatic compartment are that there is at present no need for further information and/or testing and no need for risk reduction measures beyond those which are being applied already. This conclusion applies to chlorine and its aqueous transformation products hypochlorous acid and hypochlorite, and to halogenated by-products.

Chlorine releases to the terrestrial environment result in no free chlorine, hypochlorous acid, or hypochlorite. Thus there is negligible risk due to these compounds in the terrestrial environment, due to lack of environmental exposure and here again there is at present no need for further information and/or testing and no need for risk reduction measures beyond those which are being applied already.

The sodium hypochlorite risk assessment (http://ecb.jrc.ec.europa.eu/documents/Existing-Chemicals/RISK_ASSESSMENT/REPORT/sodiumhypochloritereport045.pdf )  uses whole effluent testing from chlorinated raw sewage to show that the halogenated by-products present did not increase the toxicity or reduce the biodegradability of the effluent. As this represents a realistic worst case, there should be no cause for concern for halogenated by-products generated by aqueous use of chlorine. The same is concluded for the atmospheric compartment.

In water, chlorine disproportionates to form hypochlorous acid and hypochlorite, which do not bioaccumulate. In the atmosphere, chlorine is not persistent, as it is rapidly removed due to photolysis. Thus chlorine does not fulfil the PBT criteria and a PBT assessment is not relevant.

 Facts : the main uses of chlorine and sodium hypochlorite (chlorine bleach)

 The main uses of chlorine are on the site of production and include mainly PVC production, non-chlorinated polymer production, production of inorganic chemicals, including sodium hypochlorite,  chloromethane production, epichlorohydrin production, production of solvents, of  chlorinated paraffins, of chlorinated acyclic derivatives, chloro aryl derivatives and chloro oxygenated derivatives.

Elemental chlorine used offsite is mainly used as an intermediate in dyestuff and pesticide production. Small other industrial offsite use of elemental chlorine as an intermediate ; it is used also as drinking water disinfectants, swimming pool disinfectants, waste water treatment or cooling water disinfection.

 Sodium hypochlorite is used for household and laundry cleaning, sanitation, deodorizing and disinfection,  municipal water, sewage and swimming pool disinfection,  medical environment disinfection, disinfection purposes in food industry and food manipulation, textile industry and pulp and paper bleaching, chemical synthesis, as a multisite fungicide in agriculture and horticulture.

In 2008, the Health and Environment Committee SCHER of the DG SANCO (European Commission) emitted an opinion on the human health part of the risk assesment of chlorine : SCHER, scientific opinion on the risk assessment report on chlorine, human health part, CAS 7782-50-5, 12 March 2008.  it can be found on :



See also :  the GreenFacts Digest “Executive Summary of the Environmental Health Criteria (EHC) 216: disinfectants and disinfectant by-products.  http://www.greenfacts.org/en/water-disinfectants/index.htm

This Digest is is a faithful summary of the leading scientific consensus report produced in 2000 by the International Programme on Chemical Safety IPCS  : http://www.inchem.org/documents/ehc/ehc/ehc216.htm

1. What disinfectants and by-products are we talking about?

2. What happens to disinfectants and their by-products when ingested or inhaled?

3. How can disinfectants and their by-products affect health?

4. Have disinfectants and their by-products affected human health?

5. What are the risks posed by disinfectants and their by-products?

6. Conclusions


Final reports, December 2007

The rapporteur for the risk assessment of chlorine and sodium hypochlorite was Italy. Contact point: Dr. Roberto Binetti (roberto.binetti@iss.it) and Dr. Leonello Attias (leonello.attias@iss.it ) Centro Nazionale Sostanze Chimiche, Istituto Superiore di Sanità, Viale Regina Elena, 299, 00161-Rome, Italy


Note : the short presentations of the reports made on the blog of GreenFacts are prepared by its editorial team but  not verified by its Scientific Committee.

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