What is mercaptan used for in natural gas?

• A. Fuel additive to increase burning
• B. Colorant to identify gas leaks
• C. Pesticide for agricultural use
• D. Odorant applied to natural gas

Answer: (D)

Mercaptan is added to natural gas to provide a detectable odor. Natural gas by itself is odorless, so leaks could go unnoticed. Mercaptans are sulfur-containing compounds with a strong, characteristic smell (often described as rotten eggs), even at very low concentrations. By odorizing the gas, people can detect leaks quickly and evacuate or fix the issue before it becomes dangerous.

So the purpose isn’t to burn better, color the gas, or act as a pesticide—the odorant function is the key safety role. If you notice that sulfurous odor, treat it as a gas leak and take appropriate precautions.