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PRIO – A tool for Risk Reduction of Chemicals

Properties of PRIO substances

Substances with the following inherent properties are PRIO substances. The properties have been divided into two levels, depending on the degree of concern in line with the specifications in the Non-Toxic Environment Objective. Accordingly, the PRIO substances are either phase-out or priority risk-reduction substances.

Phase-out substances

  • CMR (carcinogenic, mutagenic or toxic to reproduction), categories 1A and 1B
  • PBT/vPvB (persistent, bioaccumulating and toxic/very persistent and very bioaccumulating)
  • Particularly hazardous metals (mercury, cadmium, lead and their compounds)
  • Endocrine disruptive
  • Ozone-depleting 

Priority risk-reduction substances

  • Very high acute toxicity 
  • Allergenic 
  • Mutagenic, Category 2 
  • High chronic toxicity
  • Environmentally hazardous, long-term effects 
  • Potential PBT/vPvB


The above-mentioned criteria are used to determine if a substance has phase-out or risk reduction properties. To establish whether a substance fulfils the criteria, a comparison is made on the basis of available test data and/or other information on the substance. A detailed account of the type of information required for this assessment is given in the section The Criteria in detail. The PRIO tool recommends the user, as far as possible, to replace those substances that fulfil the phase-out criteria with less hazardous substances or use of alternative methods. For substances meeting the risk reduction criteria, PRIO tool recommends the user to review the risk of the envisaged use. I.e. manufacturers, importers, suppliers and users of chemical products and other articles should conduct a risk assessment to aid identification of necessary risk reduction measures and to ensure that the substance does not pose unacceptable risks at any stage of handling.