Final answer:
Environmentally friendly gases, such as noble gases, cause the least environmental damage during a leak check due to their inert nature. Methane is another gas that, while contributing to the greenhouse effect, is less harmful in its pure form. Noble gases like krypton and xenon are ideal as they disperse quickly and do not integrate into the food chain.
Step-by-step explanation:
When performing a leak check, using gases that cause the least environmental damage is crucial. The most environmentally friendly gases are those that do not contribute significantly to pollution or global warming, such as noble gases like helium, neon, argon, krypton, and xenon. These gases are chemically inert and do not react with other substances in the environment, hence not causing pollution or contributing to chemical reactions that harm ecosystems.
Methane (CH4) is a common gas that is lighter than air and often used in leak checks. While methane is a greenhouse gas, it is non-toxic and will not contaminate groundwater or surfaces. During a leak, methane would rise and disperse quickly, minimizing potential environmental damage compared to other industrial gases.
Krypton and xenon, noble gases, were mentioned concerning the Three Mile Island incident. They readily disperse in the atmosphere, do not create highly radioactive areas, nor are they incorporated into the food chain. Such characteristics make krypton and xenon preferable in scenarios where the release of gases is inevitable.