The subject you are trying to discuss is fully organized in the United Nations Organization (UNO) Charter, with An International related Laws and Authorities. However, within the National Laws of each UNO Member Nation, the question may be different, while usually the matter must follow the UNO Guide Lines. Therefore, you should checkout the related details within the laws of each Nation Member.

For Canada, this a verbatim passage concerning that issue:

Compliance and Regional Operations

Working with other federal and provincial ministries, PMRA regional offices promote and verify compliance with the PCP Act through investigations, inspections and consultations. They have the mandate to investigate the use, sale and importation of products; perform on-site inspection of usage and storage of products; do soil, crop and product sampling; and to educate individuals, local officials and grower groups as to regulatory requirements. Where contraventions of the Act or regulations occur, appropriate enforcement measures may be taken.

See

https://www.canada.ca/en/health-canada/services/consumer-product-safety/reports-publications/pesticides-pest-management/fact-sheets-other-resources/regulation-pesticides.html

To add to Charles' answer, once the PMRA "detains" a pesticide, it usually remains on the premises where was found. It then must be disposed of in an approved manner. This usually means sending it to a hazardous waste disposal site. The person must show evidence that this was done (typically a bill of lading from a recognized hazardous waste disposal company.) or be deemed in contravention of the Pest Control Products Act