I have recently come across a woeful comment on the future ‘ban’ of one of the staple solvents in chemistry: N,N-dimethylformamide, usually referred to as DMF. I decided to take a look for myself into some of the legal proceedings of the European Union and this is what I found.
First, a tiny bit of background; all the regulations under discussion only apply to EEA countries. In 2006, the Regulation (EC) No 1907/2006 concerning ‘Registration, Evaluation, Authorisation and
Restriction of Chemicals (REACH), establishing a European Chemicals Agency’ was passed by the European Parliament and the Council of the European Union. In the ‘Recitals’ section (as I’ve been told by someone knowledgeable it’s called, thank you!), entry 25 (page 10) indicates that it is the responsibility of manufacturers and importers of substances to assess the risks and hazards of those substances, and of those handling the substances to follow the prescribed ‘risk management measures’.
In 2018, the Italian Ministry of Health submitted a request (Annex V Proposal for a Restriction concerning DMF) to the European Chemicals Agency to amend the legislation concerning use of DMF, under the terms described in the Regulation (EC) No 1907/2006.
I think it would be interesting to cover the scientific method backing this request:
- Setting DNEL (Derived No-Effect Level) values. Using reported toxicological studies and REACH guidelines, the maximum amount of DMF to which humans can be exposed on a long-term basis, either via inhalation or by dermal contact, is set. These levels indicate the maximum amount humans can be expected to tolerate without noticing adverse health effects.
- Estimating the expected exposure for different scenarios: DMF manufacture, its use in petrochemical, polymers, and leather, fur, and textiles industry, formulation, fine chemicals synthesis, and finally, the only registered non-industrial, professional use, as a laboratory chemical using dedicated software. Exposure is only considered for occupational purposes as DMF is not found in consumer products and it is readily biodegradable (therefore no environmental exposure).
- Risk characterisation ratios (RCRs) are calculated using the DNEL and predicted exposure values. RCRs provide a measure for the perceived risk: how much is a person likely to be exposed to, related to how much they should be exposed to. Values of RCR above 1 indicate a potential risk. From the analysed scenarios the following indicate an unaddressed risk to the operator: production of fine chemicals including pharmaceuticals (exposure via dermal contact, even with high protection level gloves), polymer and leather, fur, and textiles production (if processes are performed at elevated temperature, exposure mainly via dermal contact).
Aside: for using DMF as laboratory chemical the following statement is made: ‘professional use of DMF as laboratory agent is not expected to bear a safety concern for workers’. The Annex to this document does however mention ‘users should ensure that a sufficient and effective gloves management system is in place’ (page 297).
For the practising organic chemist working in R&D, this tells us what we already know. DMF is toxic, but can be handled safely by a well-trained and responsible chemist in a laboratory with adequate control measures. The fairly low volatility of DMF at room temperature and the adequate ventilation and containment make the risk of respiratory exposure low. Dermal contact is more of a problem as disposable nitrile gloves are not resistant to DMF.
Going back to the legal part of the story, what measure did the Annex V Proposal suggest? Certainly not banning DMF. This procedure was well-researched and the involved bodies aware that DMF does in general not have adequate replacement available and ‘banning of the manufacturing and uses of DMF, which is the ultimate consequence of an authorisation process, is not an appropriate risk management option’ (page 26). The report clearly predicts that banning DMF would cause some business to either shut down or relocate. The other Risk Management Options (RMOs) include restriction or authorisation. The authorisation route was deemed unsuitable, as not only it would involve higher costs, but ‘based on the socio-economic [authorisation] route some (uncontrolled) risks may remain’ (page 47).
And this brings us to the current affairs. On 19th November 2021, the Commission Regulation (EU) 2021/2030 was issued, which comes into force on 12th December 2021, and states that from 12th December 2023, DMF can be manufactured, sold, and used only if the DNEL values for occupational exposure of 6 mg/m3 for exposure by inhalation and 1.1 mg/kg/day for dermal exposure (values increased from the original proposal of 3.2 and 0.79, respectively) are ensured by appropriate control measures.
DMF will not be banned in the EEA. The increased costs associated with implementing the additional safety controls might result, however, in the DMF Winchester price going up. So, for those of you who need to wash your MOFs, research at will!