Diisocyanates
Diisocyanates are a group of highly reactive substances that have two isocyanate functional groups, they are typically colourless to pale yellow liquids with a pungent odour.
Overview
Diisocyanates are a group of highly reactive substances that have two isocyanate functional groups, they are typically colourless to pale yellow liquids with a pungent odour. The most commonly used diisocyanates are methylene diphenyl diisocyanate (MDI), toluene diisocyanate (TDI) and hexamethylene diisocyanate (HDI).
Diisocyanates are found in a range of products including coatings, adhesives, sealants, foams and elastomers.
They are used across a range of industries such as construction, for polyurethane production, the automotive industry, aerospace, furniture manufacturing as well as for fracture casts.
You can read more about the substance information for diisocyanates at the following link:
How exposure to diisocyanates could affect your health
Diisocyanates enter the body primarily through inhalation and skin exposure. They are potent respiratory and skin sensitizers and a common cause of asthma and allergic contact dermatitis.
Inhalation can cause dry throat, chest tightness, shortness of breath, coughing and wheezing.
There may also be nausea, vomiting and abdominal pain.
Skin contact can cause pain, redness and swelling of the skin with blisters.
Eye contact will result in pain, tearing and a swollen and red eye.
Further information on health effects and controls can be found on the following page:
Isocyanates | Health and Safety Executive for Northern Ireland
The increased instances of long-term health effects from the use of diisocyanates have led to the European Commission introducing an Annex XVII restriction on diisocyanate under the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) Regulation.
REACH Annex XVII restriction on Diisocyanates
This restriction requires that substance or mixtures that contain diisocyanates 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 24 February 2022, unless:
(1) the concentration of diisocyanates individually and in combination is less than 0.1 % by weight,
(2) or the supplier ensures that the recipient of the substance(s) or mixture(s) is provided with information on the requirements for training and the following statement is placed on the packaging, in a manner that is visibly distinct from the rest of the label information: “As from 24 August 2023 adequate training is required before industrial or professional use.
This restriction also requires that substances or mixtures that contain diisocyanates can only be used by industrial or professional users after 24 August 2023, if:
(1) the concentration of diisocyanates individually and in combination is less than 0.1% by weight,
(2) or that the employer or self-employed ensures that the industrial or professional users have successfully completed training on the safe use of diisocyanates prior to the use of the substance or mixture.
ANNEX XVII to REACH-Conditions of restriction
Training must cover as a minimum the following:
—the chemistry of diisocyanates;
— toxicity hazards (including acute toxicity);
— exposure to diisocyanates;
— occupational exposure limit values;
— 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, including practical instructions for its correct use and its limitations;
— risk of dermal contact and inhalation exposure;
— risk in relation to application process used;
— skin and inhalation 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 or documented proof that training has been successfully completed must also be provided.
There is also additional training required for certain uses of diisocyanate containing products as detailed in the restriction.
Training providers
As part of the Annex XVII REACH restriction the European Commission required the suppliers and manufacturers of diisocyanate containing products to provide training material and courses that met the requirements detailed above.
As such the manufacturers and trade associations have set up an online training platform that covers all the aspects of the training required with general training and use specific modules.
Safe Use and Handling of Diisocyanates Training
There are also other online diisocyanate training providers, and several local training providers are offering the training in line with the restriction’s requirements.
To ensure the training meets the requirements of the restriction, please ask the training provider to provide confirmation that the training covers the requirements set out in the Annex XVII REACH diisocyanates restriction or check the syllabus against the requirements listed in the restriction.
Professional and industrial users
Before using products containing diisocyanates above 0.1% by weight, industrial and professional users must complete diisocyanate training.
Users should at first check the products they are using to determine if they contain diisocyanates at above 0.1% by weight.
This information can be found on the label, in the safety data sheet (SDS) or suppliers will be able to help in determining products that contain diisocyanates above 0.1% by weight.
Once these products are identified, users must undertake the required training. This training normally takes the form of a short course and a competency assessment to determine understanding.
Training providers should then provide a certificate or documented evidence of training completion for your records.
Training must be repeated every 5 years.
Suppliers of diisocyanate containing products
As per the restriction requirements suppliers of products containing diisocyanates above 0.1% by weight must ensure that the packaging includes the statement “As from 24 August 2023 adequate training is required before industrial or professional use.’’
They are also required to ensure the recipient of the substance or mixture is provided with information on the training requirements.