In the United Kingdom the Health and Safety Executive for some years has stored chemical exposure data in their National Exposure Database. However, it has been difficult to persuade industry and other organizations to contribute to this resource. The aim of this project was to devise a cost-effective method of obtaining occupational exposure data on chemicals from U.K. industry and other sources. Five strategies were used to identify data for three different substances: toluene, acrylonitrile, and ethylene oxide. In total, 810 organizations were contacted and over 45 percent responded. However, only 40 had relevant exposure data. Almost equal numbers of acceptable measurements were identified for toluene and acrylonitrile (2,770 and 2,000 respectively) with lesser ethylene oxide data (800). These measurements were drawn from a wide range of industries and are probably representative of measurements made by U.K. industry, although most of the data were from companies employing more than 100 people. During the second phase of the project, more than 3,000 measurements and associated contextual information were collected (499 for toluene, 1,516 for acrylonitrile, and 17 for ethylene oxide, with a further 1,004 measurements for 1 of 27 substances collected simultaneously with one of the above). The costs of identifying and collecting exposure data ranged from ł7 to ł380 per valid measurement, depending on the source of the data. We suggest that, rather than trying to retrospectively collect data, it is likely to be more cost-effective to enlist a number of occupational hygiene consults and industrial organizations to prospectively provide anonymized exposure measurements for inclusion in the Health and Safety Executives National Exposure Database.