Chlorinated Paraffins
What are Chlorinated Paraffins (CPs)?
Due to their similar technical properties, various open applications of PCBs, such as caulks, flame retardants and plasticisers, were replaced by Chlorinated Paraffins (CPs) in the 1980s. However, also CPs are persistent, toxic and bioaccumulative.
Chlorinated Paraffins are classified into three different categories: Short-Chain Chlorinated Paraffins (SCCP), Middle- and Long-Chain Chlorinated Paraffins (MCCP/LCCP). SCCPs were added to Annex A of the Stockholm Convention in 2017.
Properties
Chlorinated Paraffins are resistant to chemicals, light and temperatures up to approx. 200 °C. They are are only slightly volatile and hardly flammable.
Like PCBs they have softening and corrosion-inhibiting properties. CPs are persistent and non-biodegradable.
Usage and applications
Chlorinated Paraffins have been used in a wide range of open applications, such as lubricants and coolants in metalworking fluids, as additives in PVC, paints, varnishes, anti-corrosion protection, adhesives, caulks/sealants, and leather fat liquors, and as flame retardants in rubber and textiles.
Some typical applications of CPs in buildings:
- Caulks/sealants
- Paints
- Varnishes
- Anti-corrosion coatings
Risks
All Chlorinated Paraffins are persistent, but SCCPs are particularly dangerous to the aquatic environment.
SCCPs can cause toxicological effects in mammals. They may affect the liver, thyroid hormone system and the kidneys by causing hepatic enzyme induction and thyroid hyperactivity. This can lead to carcinogenicity in these organs in the long-term. The substances are classified as suspected of causing cancer, and are listed as category 1 endocrine disruptors for human health.
If CPs are exposed to extreme heat or fires, highly toxic furans may be formed and released.
Not much information is available on concentrations of CPs in indoor air. It is assumed, however, that using products with low-chlorinated Chlorinated Paraffins (with short to medium chain length) has a relevant impact on indoor air.
Laws and regulations
Short-Chain Chlorinated Paraffins were added to the list of POPs (Peristant Organic Pollutants) in the Stockholm Convention in 2017.
In addition, SCCPs are listed in the Rotterdam Convention.
