I remember when I was first introduced to Registration, Evaluation, Authorization and Restriction of Chemicals, or REACH, requirements.
It seemed like such a huge undertaking to simply create a Safety Data Sheet, or SDS, for substances. Chemical safety reports had to be created and submitted. With this information, the exposure scenarios could be developed and then appended to the SDS of substances.
Were we thinking at the time what will happen with all this information when these registered substances are included in our mixtures? Honestly, it did cross my mind … for a few seconds. I imagined all these exposure scenarios appended to the mixture SDS and wondered how anyone would be able make sense of all this information. The task seemed so daunting.
A few years have passed since the crazy rush of creating exposure scenarios for registered substances. Now, we are faced with this daunting task of developing an approach that is both pragmatic and meaningful for communicating safe-use information of mixtures to downstream users in a useable format.
Two approaches have been proposed: the “top-down” approach and the “bottom-up” approach.
The starting point of the “top-down” approach (The Lead Component Identification, or LCID) is based on the information from those substances that are contributing to the exposure for each end-use. The theory is that if the exposure risks are controlled for the most hazardous substances contained in a mixture, then the risks will be controlled for the other substances as well.
The starting point for the bottom-up approach is focused on understanding the end-use of the mixture for a specific industry sector. Take professional spray painting in a near-industrial setting as an example. Organizations such as CEPE (the Paint, Printing Ink and Artists’ Colours Council in Europe) have made great strides in clearly defining markets and uses for their areas of coverage. They have developed 17 Sector-specific Worker Exposure Descriptions and the corresponding Safe Use of Mixtures Information, or SUMIs.
For the bottom-up approach, formulators can append the SUMI to their SDS or include safe use information throughout their SDS. On the other hand, for the top-down approach, formulators can include safe-use information throughout their SDS, develop consolidated safe-use information of the final mixture or include lead substance(s) Exposure Scenario(s) with safe use information of the mixture.
Which approach should be used really depends on your mixture and business sector.
If an industry sector specific bottom-up approach is available, meaning that the industry sector has developed a SUMI that coincides with your mixture end-use, then this approach would be applicable. It seems simple at the high level: Select the SUMI that matches your end-use and call it done. But this is not the case. A verification check is required to ensure that the SUMI is aligned with the Sector-specific Workers Exposure Description, or SWED, of the contributing substances in the mixture. How this is accomplished varies by industry.
It is important to understand that there could be more than one SWED applicable to your mixture since some SWEDs may be activity-specific while others cover the whole process that a worker will have to perform. So what happens if your SWED is not aligned with the substance-exposure scenario? Then you can reach out to your supplier and request that their Chemical Safety Report be updated, or you can perform your own Chemical Safety Assessment. If all else fails, you can apply the top-down approach. The verification step seems to be the most tedious task of the bottom-up approach but necessary.
No matter the approach, the underlying issue will be how to distribute this information in a streamlined and usable format throughout the supply chain. The recommendation is ESCOM XML. This leads to a host of new implications and questions. How many companies and suppliers will implement this process? Time will tell. But, as I mentioned earlier when I was first introduced to REACH requirements, creating substance-exposure scenarios seemed a daunting task but we were able to get it done. We will find our way through mixture safe-use information, and we will find a way to effectively communicate information to send users downstream one way or another. After all, ensuring the safe use of products for workers is the driving force behind all these regulations and guidelines and therefore a worthy endeavor!