Air Force records prepared by AFMC at Davis-Monthan AFB in 1996 indicate at least eight of the C-123K aircraft sold or otherwise provided to foreign governments are "suspected of Dioxin Contamination". Often as aircraft age and the United States retires them, other friendly countries purchase the planes or the US provides them as military support.
Foreign sales or transfers are managed out of Wright-Patterson AFB by the Air Force Security Assistance Center. I've requested information about whether these governments have been told about the "suspected dioxin contamination" but have not yet received an answer from AFSAC. Air Force records also indicate that the Air Force Environmental Law Division (Major Ursula Moul) in Oct 1996 recommended keeping such information within "official channels", so it may be that no notice was ever provided foreign users. In one memo she said she'd be doing something about notifying the buyers...but that notification is very hard to find...we're still looking, and so is the Air Force. Must be somewhere. She wouldn't overlook a safety issue like that, right?
Leaves us with an understanding that no alert was ever provided the US aircrews whose duty it was to fly these same contaminated aircraft between 1972-1982 before the planes were distributed.