NMP restriction to take effect soon

N-Methylpyrrolidone (NMP) is used as an aprotic solvent in the manufacture of batteries, semiconductors, fibres, pharmaceuticals and wire coatings. A regulation last year added NMP to Annex XVII of REACH. From May 2020, NMP may be marketed and used only if compliance with certain exposure limits is ensured.

NMP restriction to take effect soon. Image source: sharaku1216 - stock.adobe.com
NMP restriction to take effect soon. Image source: sharaku1216 - stock.adobe.com -

By Kerstin Heitmann, Umco

NMP has a harmonised classification as toxic for reproduction and may damage the unborn child. It is therefore a CMR substance. Furthermore, it causes eye and skin irritation and may cause respiratory irritation. In 2011, NMP was added to the candidate list as a substance of very high concern (SVHC) and a proposal was made in 2018 to consider it a substance subject to authorisation (8th Recommendation for Inclusion in Annex XIV). However, when the restriction was adopted, inclusion in Annex XIV was postponed until further notice.

Content of the restriction

The restriction on NMP is intended to ensure adequate control over the health risks associated with using it. The restriction applies to the placing on the market and use of NMP, on its own or in mixtures containing ≥ 0.3 % (weight percent NMP). Marketing and use of NMP and mixtures containing it are permitted only if certain exposure thresholds are met for the workers concerned. Such No-Effect Levels (DNELs) are derived from toxicological studies and describe the levels of exposure to a substance below which no adverse health effects are expected to occur in humans. The risk is deemed to be controlled if neither the DNEL for exposure by inhalation nor the DNEL for dermal exposure is exceeded for individual workers:

DNELinhalation: 14.4 mg/m3

DNELdermal: 4.8 mg/kg bw/day

These values and the risk management measures for complying with them must be communicated to the users in the safety data sheet (SDS). DNELs are already familiar from substance registrations, but they are derived by the registrants and are not binding. The addition of NMP DNELs to Annex XVII now renders them binding across the EU and means they co-exist with occupational exposure limit values (OELs). Existing national OELs must be stated in the SDS too (in Section 8.1). The plethora of different values may be confusing at first glance, but it is expected that the national limit values will soon be withdrawn, leaving only the DNELs from the restriction in place.

ECHA guideline provides compliance advice for users

The European Chemicals Agency (ECHA) has published a guideline document to help manufacturers, distributors and users of products containing NMP to comply with the restriction. It addresses communication along the supply chain, exposure scenarios and compliance with exposure limit values.

The guideline details the various uses of NMP and what has to be observed. As it is a registered substance, suppliers of NMP must provide users with an extended safety data sheet (eSDS) containing exposure scenarios and they in turn must check to see if their particular use is covered by them, and ensure that they have the appropriate risk management measures in place. The guideline also describes the options available to users if their particular use is not covered by the exposure scenarios received from the supplier.

As for NMP in mixtures, the guideline clarifies that, although exposure scenarios are not mandatory here, information on the conditions of safe use is still provided with the safety data sheet. The user must be in a position to check the mixture safety data sheet for identified uses, conditions of use and risk management measures.

There is nothing new to this, as it describes the basic requirements for communication on the safe use of registered hazardous substances. The express description provided in the restriction serves to underscore the relevance of this information. Specific examples of how to safely use NMP in different activities are described in Chapter 3 (“Examples of good practices to control exposure to NMP”), some of which are backed up with pictures. These may also be used by suppliers who have not carried out their own chemical safety assessment for their product (where they produce/import less than 10 t/a or where NMP is contained in mixtures).

Also useful are the methods for “Monitoring and Checking Compliance” given in Chapter 4.

Relevance to the coatings industry

NMP is still frequently employed in the coatings industry, too, even though its classification as a CMR substance has meant that, under national hazardous substances legislation, a substitution test has long been obligatory. The restriction adds to the pressure to substitute less hazardous substitutes for this solvent wherever this is possible at reasonable outlay. The question as to what is reasonable then becomes moot because, as a result of the restriction, unless continued use occurs in contained systems, the outlay involved will be high.

In any event, solvents classified as reproductive toxicants are unsuitable substitutes. A proposal for a restriction on dimethylformamide (DMF) has already been submitted. And, a 2018 Risk Management Option Analysis (RMOA) by the ECHA, also recommended placing a restriction on N,N-dimethylacetamide (DMAC).

Hersteller zu diesem Thema

This could also be interesting for you!