What defines fumigants in pesticide formulations?

Fumigants are specifically defined as pesticide formulations that release a gas when applied. This gaseous state allows them to penetrate into areas that may be inaccessible to other types of pesticides, such as solid or liquid formulations. The gaseous form is essential because it facilitates the movement of the pesticide through various materials, ensuring effective pest control, especially in enclosed spaces like storage facilities, soil, or buildings.

This characteristic makes fumigants unique compared to other pesticide types, which may rely on different methods of application or mechanisms of action. Understanding this definition is critical for proper handling, application, and compliance with safety regulations associated with the use of fumigants. The other options do not accurately capture the essence of what fumigants are or their application methods.