Concentrations of lacinilene, lacinilene methyl ether, and their, precursors dihydroxycadalene and hydroxymethoxycadalene were determined in bracts as functions of cultivar, growing location, and year and in mill dusts as functions of particle size and growing location. TLC and reverse phase HPLC were used to quantitate the compounds. Concentrations of these compounds in bract powders were significantly different among the cultivars: 'Deltapine, 61,' highest; 'Acala SJ5,' intermediate; and 'GSA71,' lowest. Concentrations in Mississippi bracts were significantly higher than those in Texas bracts which, in turn, were significantly higher than those in California bracts. Mill dust samples, compared to bracts, contained lower levels of these compounds with highest concentrations in dust from Mississippi-grown Cotton. These sesquiterpenes vary in concert with both grain (-) bacteria and endotoxin in cottons from different locations.