Cylinders used to store recovered refrigerant must be approved by which agency for transportation?

解析

Recovery cylinders must be Department of Transportation (DOT) approved for the transport of refrigerant under pressure, and they must be within their required inspection and test intervals. OSHA handles workplace safety, EPA handles refrigerant management rules, and AHRI publishes purity standards, but the cylinder approval itself is a DOT function. Using unapproved or expired cylinders is unsafe and illegal for transport.