Agent Blue: The lesser-known toxin left in Vietnam

Fifty years have passed since Vietnam's people reunified after a long and bloody struggle. Most scars from that time have healed, but not all. The chemical Agent Orange - dropped from US planes to eradicate jungles - has proven notoriously hard to remove from Vietnam's soil, even though the US has spent decades trying to do just that. As The World's Patrick Winn reports, there's another wartime chemical, Agent Blue, that's received far less attention even though it's still making people in Vietnam sick.