Humidity is the great enemy of paper

Humidity is the great enemy of paper. High average humidity levels will rust staples and discolor paper over time. Warm, humid regions pose the greatest danger: Hawaii, Florida, the Gulf Coast. But even cool humid locations like Oregon or Maine are a threat.

Two Temple of Elemental Evil game books. Bottom book spent years in a storage locker, no climate control to lower humidity levels.

See Also: AD&D Module T1-4 “Temple of Elemental Evil” – 1ST PRINT IDENTIFICATION