Health Canada has issued both an Advisory and Recall on small magnet sets (adult puzzles, Bucky Balls) for the hazard of young children putting them in their mouth.
for more information....http://healthycanadians.gc.ca/recall-alert-rappel-avis/hc-sc/2013/31619a-eng.php
and http://healthycanadians.gc.ca/recall-alert-rappel-avis/hc-sc/2013/29247r-eng.php