Monitoring of exposure to benomyl in nursery workers

We compared urinary levels of the metabolite methyl-5-hydroxy-2-benzimidazole carbamate (5-HBC) among nursery workers exposed to the fungicide benomyl (specifically Benlate 50 DF [DuPont, Wilmington, DE]) and workers not exposed to benomyl. Environmental exposures were quantitated from gloves, body patches, and air samples collected with area and personal monitors. The median concentration of 5-HBC in the urine of benomyl-exposed workers was 23.8 mumol of 5-HBC per mole of creatinine. No 5-HBC was detected in the reference group. Industrial hygiene results and biological monitoring findings indicate that use of Benlate 50 DF in the ornamental industry can lead to absorption of the active ingredient, benomyl. Weighing, mixing, and application activities involved the highest exposures. Dermal contact appeared to be the primary route of exposure.