The latest rules are linked here.

NOTE: Changes in Canadian Transportation Regulations Regarding Special Permit Shipments
Canadian regulations regarding returning shipments of scrap metal or RCRA Subtitle D materials under the special permits have recently changed. The latest rules are linked here. The change is located in the Application section 2(2)(o) and is highlighted. The rule was changed by providing an exception from the regulations instead of requiring an estoppel. Mr. Martin Thériault, has offered his name for use on the form as a contact for detections made at the Canadian ports of entry. His contact information follows:

Martin Thériault Phone: 613-991-3169 martin.theriault@canada.ca

This is not a requirement, but having the information handy may shorten or eliminate delays at the border when detections are made. Mr. Theriault’s contact information can be placed on page 3 of the authorization form in the section designated Remarks, other information.