Concentrations of various volatile terpenes and terpenoid aldehydes (TA) found in pigment glands were determined in Bracts as functions of cultivar, growing location (MS, TX, CA), year (1932-84), and time of harvest (before and after frost) and in mill dusts as functions of particle size, growing location, and year. Only low concentrations (generally less than 150 ppm) of volatile terpenes occurred in bracts and mill dust, and volatile terpenes could not be detected in dust collected from animal exposure cages. Concentration ranges of TA in bracts were: total TA (gossypol equivalents), 314-3668 ppm; extractable gossypol, 18-172 ppm; and extractable heliocides 173-585 ppm. Concentrations of TA decreased following frost, and were 20-30% higher in 'Deltapine 61' than in 'Acala SJ5' or 'GSA 71.' No consistent differences in TA concentrations occurred among locations and years. Concentration ranges of TA in mill dusts were: total TA (gossypol equivalents), 629-2540 ppm; extractable gossypol, 56-1319 ppm; and extractable heliocides, 213-847 ppm. Highest concentrations occurred in fine particles (below 75 µm), and in dusts from the Texas High Plains. Dust from animal exposure cages contained 302 ppm total TA.