A preliminary ruling by the European Court of Justice would require registration under REACh of reacted monomers in polymers. Juliane Kokott one of the Advocate Generals at the European Court of Justice (ECJ) issued an opinion rejecting the claim made by four companies that such a registration requirement is unlawful. The term monomer substances refers only to reacted monomers, that is, monomers which have reacted together in such a way that they are bound in the polymer of which they are components. This was the court’s first interpretation of the REACH regulation since its implementation. This opinion is non-binding and could be overturned.