Airborne Formaldehyde Levels During Simulated Formalin Egg Treatments in Vertical-Flow Tray Incubators at a Production Fish Hatchery.

Abstract

Formalin, an aqueous solution of formaldehyde and methanol, is widely used in aquaculture facilities to treat water molds during egg incubation. Given the carcinogenic properties of formaldehyde, an understanding of the occupational exposure of aquaculture workers is essential. This study evaluated formaldehyde levels in a production fish hatchery incubation room under six different formalin treatment scenarios: one, three, or five vertical flow incubation stacks received 1,667 mg L-1 formalin treatments for 15 min with the incubation room door either open or closed. The results indicate that the level of formaldehyde being aerosolized increased as the number of stacks treated increased, with maximum levels ranging from approximately 0.5 ppm when only one stack was treated to over 2.0 ppm when five stacks were treated and the door was closed. Having the door open during formalin treatment resulted in significantly lower aerosolized formalin levels when three or five stacks were treated and a reduction in the time required for a return to basal levels when five stacks were treated. Based on these results, it is imperative that hatchery workers are able to leave confined incubation locations or use appropriate safety equipment during formalin treatments.