What is a critical safety precaution when considering the use of phosphine?

Avoiding exposure to moisture during the application of phosphine is a critical safety precaution because phosphine is generated when aluminum phosphide or other phosphine-generating compounds react with moisture. When these compounds come into contact with moisture, they release phosphine gas, which can be hazardous to health if inhaled. By ensuring that the application is conducted in a dry environment or avoiding moisture exposure, the risk of creating dangerous levels of phosphine gas is minimized.

This safety measure is vital in preventing unintended gas release, which could lead to serious health risks for both the applicator and anyone in proximity. It highlights the importance of managing environmental conditions during fumigation processes to maintain safety standards.