It is a well known fact that dampness seriously affects dry cargoes. Moisture trapped inside a container during a long trip causes packages to soften and deform, metal cans to rust, powders to harden, etc.

The two main causes of moisture damage are "sweating" of the cargo and "sweating" of the container. "Sweating" means condensation. Both types of condensation are caused by humid air within the container, and changes in exterior temperatures.