A cholinesterase testing program for pesticide applicators

Illnesses associated with the increased use of cholinesterase-inhibiting pesticides have brought about recommendations for monitoring pesticide applicators. The State of California requires medical supervision; however, the supervision and monitoring guidelines are often incorrectly followed. In this retrospective cohort study, 103 worker-years of cholinesterase monitoring are reported. Twenty-four (24%) workers were temporarily removed from spraying (five were removed twice) because their cholinesterase plasma activity levels were below 60% of baseline. Five workers (5%) had mild symptoms of toxicity but none reported a specific incident of exposure. Hispanic workers had fewer significant drops in plasma activity levels and fewer toxic symptoms than white workers. The relative risk of pesticide poisoning was increased in workers whose initial baseline plasma levels were low or if their levels had already dropped to 60%-80% of their baseline previously in the season. Case studies and differences in baselines by month of determination suggest poor monitoring compliance by the companies and employees. Suggestions of how the physician can overcome these problems and improvements of the guidelines are discussed.