What system is commonly used to color-code oxygen tanks for safety?

The green color is commonly used to color-code oxygen tanks, which indicates that the tank contains pure oxygen. This color-coding system is designed for safety and helps divers and professionals quickly identify the contents of gas tanks in various situations, reducing the risk of accidents or improper gas handling.

Using clear color codes, the industry standard allows divers to easily recognize that a tank marked in green is safe for oxygen use, which is vital for preventing potential misfills or the use of the wrong gas during dives. This standardization not only aids individual divers but also improves communication and safety on dive boats and equipment setups, where multiple gas mixes may be present.