EU rules on the use of chemicals in manufacturing and other processes are largely governed by the REACH Regulation (1907/2006 on the registration, evaluation, authorisation and restriction of chemicals).
This provides that, where a chemical substance is used that is "of very high concern" for health or the environment because, in particular, of its carcinogenic, mutagenic or toxic properties, and if it is present in a concentration above 0.1% of the mass of an article, the producer or importer must notify the European Chemicals Agency (ECHA).
Similarly, the supplier must inform the recipient and, on request, the consumer of the article of the presence of these substances of very high concern (SVHCs).
At issue in Case C-106/14 before the EU's Court of Justice (CJEU) was the question as to whether ECHA was correct in its assessment that the 0.1% rule applied to the weight of an entire product.
In France, the stricter view was taken that it should apply to the individual articles that go to make up a complex product and eventually a federation of DIY and home improvement shops decided to seek a ruling as to which was correct.
The CJEU has come down on the French side of the argument, giving a definition of "article" and of "product" and ruling that "each of the articles incorporated as a component of a complex product is covered by the relevant duties to notify and provide information when they contain an SVHC in a concentration above 0.1% of their mass".
Furthermore, the Court has stated that the duty to provide information with regard to the recipients and consumers of the product is not restricted to the producers and importers but applies to all operators along the supply chain when that person supplies an article to a third party.
ECHA's detailed list of SVHCs can be found here.