Detectives have laid drug charges at the jail in Penetanguishene after marijuana was seized by staff members.
The OPP made the arrests last Monday.
A 67 year old volunteer is alleged to have brought almost 50 grams of pot into the jail, and two inmates were found with the drugs on them.
The drugs were valued at almost five thousand dollars by police.
All 3 men will be in Midland court.
They’re facing charges of possession of marijuana, and trafficking charges.