19 CFR 10.308 - Records retention.
(a) Importer. The importer of record shall retain the exporter's certificate of origin required by § 10.307(d) for a period of 5 years and it must be made available upon request by the appropriate Customs official.
(b) Exporter. Any person who exports, or who knowlingly causes to be exported, any merchandise to Canada shall make, keep, and render for examination and inspection, such records (including certifications of origin or copies thereof), which pertain to such exportation for a period of 5 years from the date of exportation. In the event that the appropriate Customs official requests submission of the records, they shall be submitted directly to the requesting official.