As I recall, the air tanks were provided from the begining on the 72's.
This video was shot after AC 17 pitch poled, and it shows they were certainly not being cavalier about safety. One of the sailors says; "We were fortunate no one was hurt this time. We can't assume that will always be the case".
Another says: "The drills were fun, but were also sobering. They drive home that what we do is pretty dangerous".