This NIOSH conducted study assessed the exposure of commercial nursery workers in Florida to benomyl (17804352). The study involved five nurseries at which Benlate-50-DF was used under EPA Experimental Use Only status and at two nurseries at which it had never been used. From ten exposed nursery workers, 54 urine samples were collected, and from nine unexposed workers 18 samples were collected. For exposed workers, personal breathing zone (PBZ) and dermal exposure monitoring occurred. Exposed workers had levels of methyl-hydroxy-benzimidazole-carbamate (HBC) in urine ranging from 3.0 to 87.0 micromoles/mole creatinine. The highest urinary levels of HBC occurred after weighing Benlate, with lower levels found after application and mixing activities. No control workers had HBC in their urine. During mixing, drenching and postapplication of Benlate, inhalation amounts were below the detectable limit. Quantifiable low levels were detected during weighing activities. Personal exposures to benomyl were less than 1 part per billion, as detected by the metabolite butyl-isocyanate. Benomyl was found in 37 of 38 glove samples obtained from workers directly handling Benlate who wore disposable latex gloves over cotton monitors. Benomyl was found on 15 of 16 cotton glove monitors worn by workers trimming plants outdoors 46 hours after Benlate drenching. The authors conclude that industrial hygiene results are consistent with biological monitoring findings in documenting workers with highest exposures, with weighing activities posing the highest risks.