Chlorinated paraffins: End-users need to push for alternatives
Don Smolenski, Contributing Editor | TLT Machinery April 2020
Despite ongoing regulatory concerns, these substances are still widely used in the MWF applications.
Chlorinated paraffins are very valuable MWF additives, however, there’s still debate about its safety concerning environmental and health issues.
Chlorinated paraffins (CPs) are used very effectively as extreme pressure additives in metalworking fluids and some industrial lubricants. They are complex mixtures of polychlorinated n-alkanes and are subdivided by their carbon chain length, with short-chain CPs (SCCPs) having a chain length of 10 to 13, medium-chain CPs (MCCPs) 14 to 17, long-chain CPs (LCCPs) 18 to 20 and very long-chain CPs (vLCCPs) 21 or greater. The degree of chlorination can vary between 30 and 70 wt%.
Depending on their degree of chlorination, SCCPs are classified as persistent, have a high potential for bioaccumulation, are carcinogenic to rats and mice and toxic to aquatic organisms. Effective December 2018, SCCPs were globally banned under the Stockholm Convention on Persistent Organic Pollutants. The U.S. EPA was planning to ban MCCPs and LCCPs in 2016 under the Toxic Substances Control Act (TSCA) because they may present an unreasonable risk to aquatic organisms and may be very persistent and bioaccumulative. However, manufacturers of CPs and the Chlorinated Paraffins Industry Association (CPIA) lobbied EPA that such a ban would detrimentally impact their customers. EPA had entered into consent orders with three companies that allowed them to manufacture and import medium-, long- and very long-chain CPs.
A future Significant New Use Rule was set to require manufacturers and importers of CPs to conduct aquatic toxicity and biodegradability testing over five years. After President Trump took office, the Trump administration decided to review medium- and long-chain CPs as existing, rather than, new chemicals under TSCA. Quite a bit of legal wrangling followed, with the end result that would likely lead MCCPs, LCCPs and vLCCPs to be permitted. This saga has been going on for at least a decade, and I find myself wondering what CPIA and member companies have done to develop less problematic alternatives to CPs during that time.
About a decade ago, a group in GM engaged internal stakeholders from production, health and safety, environmental, waste treatment, the GM LS2 standards group and others to develop more rigor toward a common process for specifying and sourcing metal-removal fluids. As an end-user potentially affected by the CP situation, this group in GM decided to evaluate potential alternatives to CPs. Once suitable alternatives were identified, their performance in plant operations verified and cost implications quantified, GM phased out MWFs containing CPs. I strongly supported this because of concerns over worker health and the environment. With respect to the former, I had many friends in the plants (machining plants in particular), and I had vowed to always to do whatever I could to help protect worker health. With respect to the latter, as the leader of the GM used oil recycling program at that time, I well understood the impact of even small amounts of CPs to the cost of disposal/recycling of used oil streams.
End-users, you have the leverage to require your fluid suppliers to identify alternatives to chemicals of concern such as chlorinated paraffins.
Don Smolenski is president of his own consultancy, Strategic Management of Oil, LLC, in St. Clair Shores, Mich. You can reach him at donald.smolenski@gmail.com.
REFERENCES
1. Rossberg, M., Lendle, W., Pfleiderer, G., Tögel, A., Dreher, E.L., Langer, E., Rassaerts, H., Kleinschmidt, P., Strack (2006), “Chlorinated Hydrocarbons,” Ullmann’s Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a06_233.pub2.
2. Cristene Villena Amauro, M.D., M.P.H., F+L Magazine, “The Truth About Chlorinated Paraffins,” January 31, 2020.
3. Several EPA, ILMA and CPIA documents.