Organophosphate exposure inhibits non‐specific esterase staining in human blood monocytes

The objective of this study was to investigate the association between exposure to triaryl phosphate and monocyte nonspecific esterase staining activity in workers from a plant in Nitro, West Virginia. A cross‐sectional study design was used to identify the exposed plant employees, and both a plant and a general population group. In addition to completing a questionnaire for each participant, 30 cc of blood were drawn and analyzed using four techniques, two morphological and two enzymatic. These procedures included a Technicon D‐90 autoanalyzer, a Technicon H‐6000 autoanalyzer, a manual enzymatic using alpha naphthyl butyrate, and a manual morphologic using Wright‐Giesma stain. The results showed a decrease in nonspecific esterase staining with the Technicon D‐90. No significant effect on monocyte numbers or esterase positivity was found with the other three techniques.