In Ontario, the re-qualification of refillable propane cylinders must follow procedures established by?

The correct answer is based on the regulatory framework governing the re-qualification of refillable propane cylinders in Ontario. The CGA, or Canadian Gas Association, is responsible for developing standards and guidelines relevant to gas installations and equipment, including propane cylinders. Their procedures outline the industry best practices for requalification, ensuring safety and compliance with national standards.

It's important to note that while other organizations like Transport Canada, ULC (Underwriters Laboratories of Canada), and TSSA (Technical Standards and Safety Authority) play significant roles in the regulation and safety of gas systems, the specific procedures for re-qualifying refillable propane cylinders are established by the Canadian Gas Association. Their focus on the safe handling and maintenance of gas apparatus directly contributes to safety in the propane industry in Ontario.