The detection of gram-negative bacterial endotoxins in occupational dusts, specifically those from agricultural environments, is of increasing importance in research on occupational lung disease. In this study, the quantitative chromogenic Limulus amebocyte lysate test for the detection of endotoxins in airborne dusts from spring wheat and oats was examined. Different extraction fluids were tested, as were the effects of time on extraction and of repeated freeze-thaw cycles on the extracts. The data suggest that the chromogenic method can be used effectively in the analysis of environmental dusts or their frozen extracts for endotoxin quantitation. Water appears to be the preferable extraction medium, and the length of extraction time may affect the results.