Plastic, synthetic ropes, natural fiber ropes, electrical cable insulations, and a wood panel were partially exposed in the black, bottom sediment of Port Heuneme Harbor to determine the effect of hydrogen sulfide on materials. After one year of exposure, the materials were recovered and examined for fouling and biodeterioration. In addition, hardness and moisture absorption tests were conducted on the plastic panels while tensile strength tests were conducted on rope specimens. Significant changes in hardness and moisture absorption were registered by nylon and phenolic laminate plastics. Decrease in tensile strength was experienced by all of the synthetic rope specimens. The natural rope specimens were totally destroyed by marine organisms. The wood panel was riddled by marine borers.