The Montreal Protocol has had great success in reducing the production and use of a number of known ozone depleting substances. As a result many alternatives to the banned substances have been developed. Some of these substances have, however, themselves ozone depleting properties or can be hazardous to the environment in other ways. As the procedure for including new ozone depleting substances under the regulation of the Montreal protocol is rather time consuming the parties to the Montreal Protocol have decided to encourage parties to take measures to actively discourage the production and marketing of new ozone depleting substances. Further it was decided to request parties to report to the ozone secretariat on new substances. EU has taken the effort to elaborate a table of 'New substances with ozone depletion potential'.Based on this list a shorter list of 7 substances of concern has been prepared by the Nordic Ozone Group for assessment in this study. The overall objective of the study is to contribute to the work on the protection of the ozone layer eventually by providing information which would facilitate the inclusion of new substances under the Montreal Protocol or by otherwise reducing the use of these substances if appropriate.