Caroline Raine discusses the future of diisocyanates and the need for training before the use of diisocyanates in the workplace.

Background

Diisocyanates are used in coatings, adhesives and sealants and are a family of chemical building blocks mainly used to make polyurethane products. Polyurethane (PU) is a plastic material (a polymer- made from smaller chains of monomers) that is derived from the chemical reaction between diisocyanates and polyols.

  • Widely used in the adhesives and sealants industry are the aromatic diisocyanates methylene diphenyl diisocyanate (MDI) and Toluene diisocyanate (TDI).

  • Hexamethylene diisocyanate (HDI), methylene dicyclohexyl diisocyanate or hydrogenated MDI (HMDI) and isophorone diisocyanate (IPDI) are aliphatic diisocyanates.

  • Polyols, which are long alcoxyether chains, which when mixed with diisocyanates polymerise forming polyurethanes.

Diisocyanates are classified as potential human carcinogens and are known to cause occupational asthma and other lung problems, as well as irritation of the eyes, nose, throat, and skin.

Draft Commission Regulation amending Annex XVII to Regulation (EC) No 1907/2006 of the European Parliament and of the Council concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) as regards diisocyanates

This draft regulation was published in September 2019 with a date for receiving comments by 15 November 2019.

According to the European Commission “this draft Regulation relates to a new entry of Annex XVII to Regulation (EC) No 1907/2006. It would restrict the use of diisocyanates as substances on their own, as a constituent in other substances or in mixtures for industrial and professional use(s), individually or in any combination of these di-isocyanates, in a concentration above 0.1% by weight. A derogation is provided for the placing on the market and use of these substances and mixtures if the employer or self-employed worker ensures that adequate training is successfully completed by the industrial and professional users prior to their use. Application of the restriction is deferred for 2 years for use and 18 months for placing on the market of diisocyanates to allow sufficient time to adapt and achieve compliance with the regulation.”

“The exposure to diisocyanates in a concentration, individually or in any combination, equal to or greater than 0.1% by weight of the substances or mixtures poses a risk to human health, in particular a risk of occupational asthma in workers. The aim of the restriction is to prevent worker exposure to diisocyanates; if sensitisation is prevented by the exposure to these substances, elicitation of hypersensitivity reactions upon reexposure would be avoided. The transitional period (2 years for use, 18 months for placing on the market) before the application of the proposed restriction will allow stakeholders sufficient time to comply with the proposed restriction and to ensure adequate communication throughout the supply chain.”

In March 2020, an answer to comments was provided by the European Commission and the intention is to implement the draft regulation.

The regulation amends ANNEX XVII of the REACH regulation and restricts the use of diisocyanates as substances on their own, as a constituent in other substances or in mixtures for industrial and professional use unless:

  • the concentration of diisocyanates individually or in combination is less than 0,1% by weight, or

  • the employer or self-employed ensure that industrial or professional user(s) have successfully completed a training on the safe use of diisocyanates prior to the use of the substance(s) or mixture(s).

It also states that it shall not be placed on the market as substances on their own, as a constituent in other substances or in mixtures for industrial and professional use(s) after unless:

  • the concentration of diisocyanates individually or in combination is less than 0,1% by weight, or

  • the supplier ensures that the recipient of the substance(s) or mixture(s) is provided with information including information on the packaging and receives adequate training required before industrial or professional use.

The training may be given online but must consist of;

General training on:

  • chemistry of diisocyanates

  • exposure to diisocyanates

  • how sensitisation can develop

  • odour as indication of hazard

  • importance of volatility for risk

  • viscosity, temperature, and molecular weight of diisocyanates

  • personal hygiene

  • personal protective equipment needed and its limitations

  • risk of dermal contact

  • skin protection scheme

  • ventilation

  • cleaning, leakages, maintenance

  • discarding empty packaging

  • protection of bystanders

  • identification of critical handling stages

  • specific national code systems (if applicable)

  • behaviour-based safety

  • certification requirements for attendees.

Intermediate level training on:

  • specific personal protective equipment needed and its limitations

  • behaviour-based aspects

  • maintenance

  • management of change

  • evaluation of existing safety instructions

  • risk in relation to application process used

  • certification requirements for attendees.

Advanced training on:

  • any additional certification needed for the tasks that are covered

  • spraying outside a spraying booth

  • open handling of hot or warm formulations (>45°C)

  • certification requirements for attendees.

The following uses must be covered:

  • handling open mixtures at ambient temperature (including foam tunnels)

  • spraying in a ventilated booth

  • application by roller

  • application by brush

  • application by dipping and pouring

  • mechanical post treatment (eg cutting) of not fully cured articles which are not warm anymore

  • cleaning and waste

  • any other uses with similar exposure through the dermal and/or inhalation route

  • handling incompletely cured articles (eg freshly cured, still warm)

  • foundry applications

  • maintenance and repair that needs access to equipment

  • open handling of warm or hot formulations (>45°C)

  • spraying in open air, with limited or only natural ventilation (includes large industry working halls) and spraying with high energy (eg foams, elastomers)

  • and any other uses with similar exposure through the dermal and/or inhalation route.

Training must be repeated every five years. There will be a transition period to allow industry to implement training plans, and many trade associations are working together to help create the training packages.

Conclusions

  • Understand that there will soon be training requirements for all those in the supply chain who deal with diisocyanates and there will of course be a cost and time implication to the roll out of this training.

Last reviewed 22 June 2020