MRSL: A good beginning, but not a panacea…
An important impact of the Zero Discharge of Hazardous Chemicals (ZDHC) Initiative’s has been the development of the Manufacturing Restricted Substances List or MRSL. This document has been developed with inputs from Brands and Chemical Industry Experts (The Technical Advisory Committee) – although predominantly the European part! Slowly and surely, it is becoming an industry standard and a step towards a harmonized approach for chemical restrictions. The MRSL shifts the emphasis on input chemical management- rather than end-of-pipe restrictions, which was the emphasis of the RSL. It also expands the scope of chemical restrictions to the manufacturing stages and supplier facilities. The idea is based on the concept – although slightly flawed – that Clean Inputs = Clean Outputs.
Although the MRSL is a good beginning, it is not the panacea for Zero Discharge goals. There are some shortcomings that need to be worked around before one can make reliance on MRSL compliance as a solution to the ZDHC goals:
- The MRSL basically implies a ban on intentional use of restricted substances. It does allow for unintentional impurities of these substances in commercial formulations through limit values in ppm. Obviously, no chemical manufacturer is actually going to monitor these limits in each batch of formulation that is produced. So, conformance by chemical manufacturers to these limit values for unintentional impurities is left to individualized approaches and is not defined!
- The Usage Ban for substances in MRSL inhibits the inclusion of substances such as Formaldehyde and in –can biocides that are used intentionally in chemical formulations, but will result in values below the maximum allowable concentration on final product. Conformance to the MRSL will still not mean that other RSL substances such as formaldehyde or Isocyanates or unreacted monomers or Biocides restrictions will be met.
- There is really no co-relation between the MRSL and RSL limit values. For example, is there a guarantee that the MRSL limit value of 500 ppm for unintentional contaminations of APEOs will mean that the limit value of 100 ppm in most Brand RSLs will be achieved in the final garment on which the APEO-based formulation has been used? What happens if I use a dye, where the amine content is 200 ppm (the limit value in the MRSL) and apply 15% of it to colour a fabric? This might lead to 200 ppm x15% =30 ppm of the amine on the fabric, which is higher than the 20 ppm stipulated under Chinese Law and in most Brand RSL documents! Also, why are there limit values of ‘unintentional contaminations’ for Allergenic Disperse dyes and carcinogenic dyes? They have to be simply not used, isn’t it?
- There is also no co-relation between the MRSL limit values and the recently published ZDHC wastewater guidelines. Again, can a formulation with allowable impurities of 500 ppm NPEO ensure that APEO in the wastewater is below 5 ppb?
- The MRSL should supposedly lead to ‘Positive Lists’ from chemical manufacturers, where they declare that their products not only do not contain intentional use of the MRSL substances, but also that any potential impurities will be below the stipulated limits. This is actually a paradox because it would be nearly impossible for a chemical manufacturer to know if these substances are present in trace levels in their formulation ‘unintentionally’ as there was no intention for these to be present in the first place!
- A normal approach to check for unintentional contaminations in chemical formulations is to test these formulations. But this is fraught with inconsistencies, as there are no established standard test methods for many of the MRSL analytes. Also, testing of emulsions and polymers is a big challenge, unless the test is done by application of these on actual substrates.
The next steps for ZDHC after MRSL
The MRSL is being adopted as an Industry Standard. It has been developed by relevant stakeholders of the industry for implementation across all supply chain tiers. It is a genuine harmonized approach from Brands & Retailers, irrespective of their product ranges or manufacturing requirements. It is the first common protocol that can be easily understood and readily implemented by raw material suppliers.
The ZDHC should now proceed to do the same with the RSL – the chemical restrictions for finished products. Today, the different RSLs from Brands & Retailers are leading to confusion amongst raw material and chemical suppliers. The RSL has unfortunately become a sort of ‘beauty contest’ or a ‘holier than thou’ approach between Brands. The substances list and limit values are quite impractical and illogical in many cases. So, is it possible to build a common industry standard for chemical restrictions in end articles that is accepted by all the ZDHC member Brands? The AFIRM RSL is one such effort and quite a few Brands are now trying to align their RSLs with the AFIRM RSL. It would be great for suppliers of ZDHC Signatory Brands to receive a single RSL document – called as the P-RSL (Product RSL)- to differentiate it with the M-RSL, from the ZDHC Signatory Brands!
Once a harmonized P-RSL is in place, the next step would be to work again on the MRSL so as to co-relate it to the P-RSL in terms of the substances list, usage ban and limit values for all P-RSL substances, including those that are intentionally used in formulations (such as formaldehyde or Isocyanates).
The ZDHC has now also published the Wastewater Discharge Guidelines, where limit values of the Priority Chemical Groups in wastewater are outlined.
An exercise can be done to work out the M-RSL limit values on the basis of a Mass- Balance equation such that they are co-related to the P-RSL and the Wastewater guideline (WW-RSL) limit values for each Substance Group. This means that:
M-RSL limit value = P-RSL value + WW-RSL value
Only then will the premise of clean inputs = clean outputs work in practice. Only then would conformance to the MRSL by chemical suppliers be able to help in meeting product restrictions and wastewater discharge norms. And only then would the different tools of ZDHC make sense to the supply chain stakeholders!