Several new chemical substances have been added to the list of hazardous products that are prohibited or strictly controlled by Regulation EC 850/2004 on persistent organic pollutants (POP). The amendment to the regulation, adopted on 26 August, is in line with the decision approved at the Fourth Conference of Parties to the Stockholm Convention, held in Geneva (Switzerland) from 3 to 8 May 2009. The chemical substances added to the list of prohibited POPs are: four types of polybromodiphenyl ether, alpha hexachlorocyclohexane, beta hexachlorocyclohexane, perfluorooctane sulfonic acid, its salts and perfluorooctane sulfonyl fluoride, and pentachlorobenzene.