The prevalence of occupational asthmogen exposure was examined. Data covering 4,490 industrial facilities were obtained from the National Occupational Exposure Survey of 1980 to 1983. The 367 occupational asthmogens of interest included allergens, irritants, and pharmacological bronchoconstrictors. Connecticut and New York City exposure data estimates were based on national findings. A total of 7,864,000 workers, 40.2% of the production workforce and 23.5% of the total workforce, were potentially exposed to asthmogens. Potential exposures per worker (EXP/W) averaged 4.43 among all occupations investigated. Although the numbers of potentially exposed workers (EXP/PWF) varied from 398,000 to 856,000 in the health services, special trade contractors, machinery, and fabricated metal products industries, the numbers of EXP/W were relatively low, ranging from 2.40 to 5.74. In the water transportation, transportation by air, miscellaneous repair, and primary metal industries, the numbers of EXP/PWF were relatively low, ranging from 23,000 to 228,000, despite the high numbers of EXP/W, ranging from 8.41 to 11.94. High quantities of both EXP/PWF and EXP/W were determined for the apparel and other finished products, transportation equipment, and food and kindred products industries. The most significant combination was calculated for the apparel industry, with a mean EXP/PWF of 463,000 and a mean EXP/W of 10.37. The unprotected EXP/W in the apparel industry were highest for production helpers, with a mean value of 37.68. In Connecticut, the highest numbers of EXP/PWF were determined for the health services and business services industries, with values of 32,000 and 16,000, respectively. In New York City, the highest number of EXP/PWF were also found in the health services and business services industries, with values of 79,000 and 57,000, respectively. The authors conclude that many production workers are potentially exposed to asthmogens. These findings stress the importance of continued hazard assessment at the national level.