Containers, other than aluminum, must be what after being involved in a fire and showing no distortion?

For containers that are involved in a fire but show no distortion, the correct action is to have them requalified. Requalification is necessary to ensure that the container still meets safety standards and can be safely used after exposure to high temperatures. Even if there is no visible distortion, the structural integrity of the container might still be compromised due to the heat from the fire.

Requalification typically involves a thorough inspection and testing process that assesses the container's ability to hold pressure and withstand normal operating conditions. This step is crucial for maintaining safety standards and ensuring that the container will function correctly in the future.

While recycling, disposing of, or repainting might be considered for other types of containers or in different situations, these options do not ensure the restoration of safe operational capabilities for containers that have been subjected to fire. Requalification specifically addresses the safety and integrity aspects necessary for continued use.