Wool releases a number of reduced sulphur gases during storage. The release is enhanced under UV and even sunlight irradiation or when hot (50°C). Carbonyl sulphide is the principal sulphur gas found, along with traces of carbon disulphide and, in the case of short wavelength irradiations (to 254nm), hydrogen sulphide. The presence of significant amounts of water (20-80per thousand wool weight) markedly increases the release of COS and CS 2. The results of our work agree well with general observations that suggest wool degrades through thermal or photochemical degradation of cystine-containing protein. Although wool releases COS over time it also slowly absorbs COS from air. The release of sulphur gases from fabrics into indoor museum air is probably not a critical issue considering the potential magnitude of other sources such as human bioeffluents. However, within display cases, problems are likely where wool, feathers or similar materials are displayed with metals.