D4’s long-range transport difficult to measure, assessment should be made on evaluation of all the evidence
Brussels, 5 December 2016 – CES-Silicones Europe believes that it was premature for the European Chemicals Agency's expert group for persistent, bioaccumulative and toxic chemicals (ECHA PBT EG) to reach any conclusion when assessing the long-range transport potential of octamethylcyclotetrasiloxane (D4) at its 22-23 November meeting.
Lack of redeposition potential of D4
The current numerical criteria, established decades ago, do not accurately predict the behaviour of silicone chemistry. While D4 may look like it can be transported over long distances, due to its unique combination of properties, the potential for deposition to surface water and land is very low.
Experts actually doing air monitoring of D4 in the Arctic have indicated1 “no firm conclusions can be made regarding the presence of D4 in Arctic air nor any trends in concentration based on findings in this monitoring study.” These same experts have also reported that presence of D4 in remote areas actually results from local sources and not from long-range transport.
“D4's long-range transport is difficult to assess. Remote locations for the substance may not be the same as those for “classical” persistent organic pollutants (POPs) such as PCBs”, Johanna PeltolaThies, co-chair of the PBT EG, told Chemical Watch.
At the ECHA PBT EG meeting, independent experts offered that it might be premature to draw any conclusions from the available data regarding D4.
Direct uses and releases of D4 are overstated
Furthermore, the statements about direct uses of D4 in personal care products, cleaning products and a range of other uses, are not correct. D4 is almost totally used (more than 99.5%) as an intermediate to produce silicone polymer products which contribute greatly to society and the environment – a chemistry which saves over 9 times the carbon dioxide emissions used to produce it.
Having thoroughly reviewed D4, ECHA’s Risk Assessment and Socio Economic Committees concluded in their final opinions in June that the REACH restriction is an appropriate measure to deal with D4 and agreed with the UK (dossier submitter)’s proposed targeted scope of wash-off personal care products. A POP nomination of D4 would have unjustified implications on many other important uses of D4, including polymers where D4 is unlikely to be available to be released.
Implementing the REACH restriction
Silicone chemistry works where other chemistry reach its limits. The unique properties of silicones, including their stability, durability and biological compatibility make them essential in today’s economy. D4 is a critical intermediate in the production of silicone polymers, which are used in a wide range of important applications: from life enhancing medical technologies, to renewable energy and energy saving solutions, to empowering the digital economy to construction and transportation. Because D4 is an essential building block of silicone polymers all these applications are threatened.
The REACH restriction is a targeted and proportionate and the silicone industry is committed to making it a success. We ask that any further regulatory action on D4 is postponed until the effectiveness of the REACH restriction in reducing emissions of D4 to the environment has been established.
1 Norwegian Institute for Air Research (2016) Monitoring of environmental contaminants in air and precipitation, annual report 2015. Report M-368-2015