CPSC is Consumer Products Safety Council (or something like that). Because of the possibility of sticking your finger(s) in between the FD cage and the chainring, they made Campy redesign some things in 1977-78 or so. This included the crankset, which then required an additional 1.5mm on the drive side and 1mm on the non-drive side in the spindle.

This is a good reference article, as well as Sutherland's 6th edition which you can find online.

http://www.minortriad.com/campagbb.html