Tony,
A double bottom is not secondary containment. API-650, Appendix I refers to double bottoms (whether using steel or a membrane liner) as "leak detection and leak containment. Secondary containment relates to the tank dike area. This terminolgy is mis-applied so often that some states have even referred to FRP tank bottom liners as secondary containment. Hope this helps a bit.
Tony,
I guess I did not answer your question. To the best of my knowledge, the following states require the use of undertank leak detection and leak containemnt for NEW oil storage tanks. Virginia, Florida, Alaska, New York, New Jersey, Minnestoa, Wisconsin, California... and I'm sure there are others too.
