After conclusion of the European Arctic Stratospheric Ozone Experiment (EASOE), experts met in Brussels on 7 April 1992 to discuss the present status of the ozone layer based on preliminary results. EASOE aimed to explore the potential for ozone loss in the arctic atmosphere and to determine if ozone depletion exists or is developing over the northern hemisphere. Begun in November 1991, the experiment involved over 250 scientists from the Community and EFTA. The total cost was some ECU 20 million, with contributions of ECU 7 million from the Community's environmental research programme. Cooperation between multi-national research groups will continue during the final evaluation and interpretation of the large quantity of data collected. Preliminary findings indicate that immediate danger of a "deep" ozone hole over parts of the northern hemisphere has receded. Phenomena identified during winter 1991-92 are nevertheless worrying (increase in statospheric aerosols caused by the eruption of Mt. Pinatubo in June 1991, unusually high levels of active chlorine compounds, unusually low levels of nitrogen dioxide, low ozone levels down to Central European latitudes in January/February 1992). It is considered that a "real" ozone hole could have developed at lower temperatures. This may occur during a coming winter, particularly given the continued increase of atmospheric chlorine. Future research work will be guided by results emerging from EASOE data. Present knowledge does not allow precise long-term prediction of change in stratospheric composition, and this must be reflected in Community environmental RTD, which will continue to investigate the northern stratosphere in coming winters.