Final answer:
Used refrigerant cylinders must meet Department of Transportation regulations to ensure they are shipped safely, considering the EPA's hazardous waste regulations as part of the compliance.
Step-by-step explanation:
Before shipping any used refrigerant cylinders, it's necessary to check that the cylinder meets Department of Transportation (DOT) regulations.
These are rules that ensure the safe transport of hazardous materials. Cylinders must comply also with the Environmental Protection Agency's (EPA) hazardous waste regulations, among other standards.
The cylinder's condition, labeling, and structural integrity are all factors assessed to comply with DOT standards, ensuring safety during transportation.