Nicolas Gallacier of LANXESS Deutschland GmbH explains the new labeling requirement and legal implementation for MIT following the 13th ATP published in October 2018.
Methylisothiazolinone (MIT) is one of the most common active ingredients used as a bactericide and antimicrobial substance in paints and coatings. It is added to many water-based paints in order to prevent microbiological contamination and consequences such as a change of viscosity, gas formation, a pH shift or even an unpleasant odor. Over the past ten years, MIT has been one of the essential biocidal active ingredients in all preservation systems, and it has been used as an alternative to, for example, formaldehyde releasers in consumer goods.
CAS number: 2682-20-4.
Photo: LANXESS AG
MIT classified as highly potent skin sensitizer for biocidal uses
Up to October 2018, MIT did not have a specific Annex VI entry in the CLP Regulation (Classification, Labelling and Packaging) for industrial use. Self-classification with a generic concentration limit of 0.1% (1000 ppm) was applied for skin sensitization but did not trigger a label on the end product, the usual dosage of MIT being far below this limit.
The data submitted in the Biocidal Products Regulation (BPR) dossier supported a specific concentration limit (SCL) of ≥ 600 ppm for MIT for skin sensitization, but in October 2018 the 13th ATP (Adaptation to Technical Progress) was published, classifying MIT as a highly potent category 1A skin sensitizer with hazard statement H317 “May cause an allergic skin reaction” and a specific concentration limit (SCL) of ≥ 0.0015% (15 ppm).
Hazard statements are part of the Globally Harmonized System of Classification and Labelling of Chemicals (GHS). A hazard statement is a phrase that describes the nature of the hazard in the substance or mixture.
H317 is a hazard statement related to potential skin sensitizers. Paints preserved with MIT will have to be labeled with the GHS 07 symbol (exclamation mark) plus the H317 phrase “May cause an allergic skin reaction” from May 1, 2020.
Photo: LANXESS AG
Consequences for the labeling of preparations and end products
This new limit has fundamental consequences for the use of MIT as an active ingredient in preservation systems. Effective MIT dosages are usually in the range of 50 to 200 ppm. With the new specific concentration limit of 15 ppm, products preserved with MIT will have to be mandatorily labeled with H317 as of May 1, 2020.
In the past ≥ 1000 ppm
New ≥ 15 ppm
Effective MIT dosage: 50–200 ppm
Legal implementation by May 1, 2020
An implementation period applies between publication of the 13th ATP and the obligation to use the new label. As the new MIT labeling was published by the European Commission (EC) in October 2018, all producers are still allowed to label in accordance with the old requirements until April 30, 2020, at the latest.
Effective May 1, 2020, all MIT-containing products in the market have to be labeled in accordance with the new law.
Restrictions expected for DIY uses in 2022
Based on the decision in the past made by the evaluating authorities for CMIT/MIT – another category 1A skin sensitizer with an SCL of 15 ppm – the new specific concentration limit is expected to have consequences for the approval of MIT-containing products for non-professional users after the evaluation of the active substance dossier.
According to the Note for Guidance1 issued by the Commission services responsible for biocidal products, products containing sub-category 1A substances at a concentration triggering classification as a skin sensitizer are expected to be restricted to professional users only, unless exposure can be avoided by means other than the wearing of personal protective equipment (PPE). This restriction is expected to happen in 2022, after active substance approval of MIT under the BPR.
In practice, this means MIT will no longer be used in consumer products. This has a major business impact for the preservation of do-it-yourself paints, and even professional paints for which MIT is an essential active ingredient for effective in-can preservation.
Adaptation of the preservation strategy after May 2020
With the implementation of the new labeling limits in May 2020, the choice of formulations for in-can preservation will be dramatically reduced. Not only MIT will be affected by a new classification but also zinc pyrithione, which is also used for the preservation of paints. Zinc pyrithione will be classified as a category 1B reproductive toxicant compound in the future, therefore meeting the exclusion criteria of the BPR and further limiting the choice of active ingredients for preservation.
Despite the BPR aiming to ensure safe handling of antimicrobial active ingredients and biocides, it is steadily limiting the choice of alternative preservatives. Biocide suppliers and customers are facing increasing regulatory pressure, requiring close collaboration to be able to find preservatives with sufficient efficacy that comply with the new regulatory constraints. As a competent partner, LANXESS aspires to address the new challenges by carefully following the implementation of the new regulations and providing customers with the necessary support to understand the consequences and assistance in adjusting their preservation strategies accordingly.
LANXESS continuously adapts its portfolio to meet new challenges and, if necessary, to develop tailor-made solutions to suit customers’ individual needs.
The company has not only developed a MIT-free portfolio including well-known standard formulations such as Bronopol plus CMIT/MIT or BIT plus OIT, but also offers several alternatives with DBDCB, including formulations that are completely free from isothiazolinones.
In-can biocides effectively protect paints from microbial contamination during storage in the container.They prevent the build-up of unpleasant odors, discoloration and pH changes.
Photo: LANXESS AG
It was necessary to inform consumers with allergen potential about the presence of MIT with proper labeling. However, the new drastic MIT classification and resulting restrictions on use represent a challenge for the industry because MIT is a key preservative for in-can preservation. Only close cooperation with biocide manufacturers will allow the industry to overcome the upcoming regulatory challenges and find sustainable protection systems.