Chronic Low-Level Cyanide Intoxication in an Electroplating Plant in Taiwan

Objective: This study aimed to investigate clinical symptoms among electroplating workers exposed to cyanide.

Methods: In this study, 26 silver-plating and 51 gold-plating workers completed questionnaires and were tested for urinary thiocyanates. Air cyanide, urinary thiocyanates, and clinical symptoms were compared between workers using Student t and χ 2 test and further analyzed by multivariate linear regression.

Results: Air cyanide and urinary thiocyanate were higher in the silver-plating plant than the gold-plating plant. In both plants, a dose-response relationship was observed between exposure status and thiocyanate levels. Silver-plating workers reported a higher frequency of almond odor detection, nasal bleeding, excessive salivation, skin scalding, and corrosion. Urinary thiocyanates were associated with the plant and exposure status, but not with smoking.

Conclusions: Our study suggests that silver-plating workers had higher exposure and more symptoms. Urinary thiocyanate may be a useful biomarker for cyanide exposure.