blackmustard says:
I've ordered buttons from www.buttondrawer.com before and was pleased with their service. I don't know if they'd be CPSIA compliant, but these are the brands they carry: JHB International, Dill Buttons, Treasure Cast, Blumenthal Lansing.
Good luck!
I check this link and thay have this note""This product is not intended for wear on garments by children age 12 or younger""..... :(