The same sort of lumping and caking of powdered substances previously discussed is also a major problem in industrial chemical production. Some chemicals decompose in the presence of water vapor. In other situations, water vapor can actually cause a chemical
reaction that changes the character of the product.

Atmospheric moisture is also a natural enemy to many grinding and pulverizing operations. Water vapor in contact with the product can make it resilient and difficult to grind, causing it to cling to the grinding machine and defy pneumatic conveyance from one process area to another.