When oil sits, a corrosive type of bacteria will actually grow in it. While oil normally has a preservative quality to metal, this oil harbors billions of bacteria which are caustic to metal at an unknown rate of corrosion. It is believed the ship is void of air pockets. Now knowing the hull is being attacked from two directions, Adams started measuring the corrosion rate on the exterior of the ship to give them a known variable. Research conducted during the course of the survey indicates biofouling may be inhibiting corrosion.
Exfoliation is clearly a major process causing hull decomposition.
After Arizona sank, Pearl Harbor was known to be a sewage dumping ground for many years. Ironically, the sewage may have contributed to the ship's preservation by creating a very fertile environment for marine growth. What is alarming is the rate of deterioration of the exposed parts of the wreck, especially the windward side of barbette number three. It's very emotional working around this vessel. Down there you face the reality of what happened on Dec. 7, 1941.