Chlorinated paraffins (CPs) are complex mixtures of certain organic compounds containing chloride: polychlorinated n-alkanes. The chlorination degree of CPs can vary between 30 and 70 wt%. CPs are subdivided according to their carbon chain length into short chain CPs (SCCPs, C10–13), medium chain CPs (MCCPs, C14–17) and long chain CPs (LCCPs, C>17). Depending on chain length and chlorine content, CPs are colourless or yellowish liquids or solids. 1
SCCPs dissolve in organic solvents, but not in water. They are non-flammable.
SSCP have the greatest potential to present a risk of environmental effects. 2
What are SCCPs used for?
The largest use of SCCPs is as a component of lubricants and coolants in metal cutting and metal forming operations. The second-largest use is as both a secondary plasticizer and a flame retardant in plastics, especially PVC. Other minor domestic SCCP uses are as a plasticizer and a flame-retardant additive to a variety of products including: rubber formulations, paints and other coatings, and adhesives and sealants 3
SCCPs and the environment
SCCPs are found world-wide in the environment, wildlife and humans. They are bioaccumulative in wildlife and humans, are persistent and transported globally in the environment, and toxic to aquatic organisms at low concentrations. 3
Although data are limited, the major sources of release of SCCPs are likely the formulation and manufacturing of products containing SCCPs, such as PVC, other plastics, paints, sealants, etc. and facility wash-down of spent metalworking fluids – these to mainly urban/industrial soil and waste water.
The primary non-occupational routes of exposure to SCCPs include ingestion, both directly and through contaminated food, and skin contact with products. Chlorinated paraffins have been isolated from human liver, kidneys, adipose tissue and breast milk. Due to their potential for environmental transport, SCCP exposure may occur from sources far from their use and release. For example, SCCPs have been found in breast milk samples taken from Inuit women 4.
There is potential for inhalation exposure to SCCPs in metalworking fluids from mists generated during metal shaping operations. ... There is also potential inhalation exposure to mists in uses where products containing SCCPs are spray applied such as in paints, adhesives and sealants. 3
Acute Health Effects Acute toxicity of SCCPs (C10-13) is very low. SCCPs may cause skin and eye irritation upon repeated application, but do not appear to induce skin sensitization 4.
Chronic Health Effects Chlorinated paraffins (average chain length C12; approx. 60% chlorine by weight) are listed on the International Agency for Research on Cancer's (IARC) Carcinogen List as "Possible Carcinogens." On the U.S. National Toxicology Program (NTP) Carcinogen List they are listed as "Reasonably Anticipated to Be a Carcinogen."
There are no data on fertility or developmental effects for humans. No changes in reproductive organs were observed in a 13 week study with rats and mice dosed with 5000 and 2000 mg/kg/day of an SCCP. In addition, developmental effects were observed in rats at 2000 mg/kg/day but not at lower doses 4.
Short-chain and medium-chain chlorinated alkanes are entering the environment in a quantity or a concentration or under conditions that constitute or may constitute a danger in Canada to human life or health, and thus meet the definition of "toxic" under paragraph 64(c) of the Canadian Environmental Protection Act, 1999 7.
Based on the available evidence, it is thus likely that SCCPs can, as result of long range environmental transport, cause significant adverse effects on human health and/or the environment, such that global action is warranted. 5
• EU: Declared a Category 3 Carcinogen in 2004 6
• REACH specifies restricted use
• SCCPs are prohibited from manufacture, use, sale, or import in Canada through their listing in the Prohibition of Certain Toxic Substances Regulations, 2012
3 US Environmental Protection Agency (EPA)
4 United Nations Environment Programme (UNEP)
5 Stockholm Convention on Persistent Organic Pollutants: Risk Profile for Short-Chained Chlorinated Paraffins, 2007
6 Category 3: Substances which cause concern for humans, owing to possible carcinogenic effects but in respect of which the available information is not adequate for making a satisfactory assessment.
7 Canadian Environmental Protection Act, 1999 (CEPA)