Why should compressed gas containers not be placed on ledges or unprotected platforms?

Compressed gas containers should never be placed on ledges or unprotected platforms primarily because if they were to fall, the potential for a dangerous situation is significantly heightened. When a container falls from a height, especially more than half of its height, the risk of it bursting or creating a hazardous leak increases, which can result in a catastrophic release of gas. Depending on the nature of the gas, this could lead to fires, explosions, or exposure to harmful substances, making proper storage and handling critical for safety in any laboratory setting.

In contrast, the other options, while they may reflect concerns related to gas containers, do not address the specific risks associated with falling. Using space efficiently is important, but it does not ensure safety. While leaking gas under pressure is a valid concern, it is more relevant to the integrity of the container rather than its height placement. Similarly, the weight of the containers is an important consideration for handling but does not pertain to the risks posed by their placement on unprotected ledges or platforms.