___________________ is added to propane to increase the likelihood that a leak will be detected.

• A. Dye
• B. Lubricant
• C. Odorant
• D. Colorant

Answer: (C)

Propane is odorless, so an odorant is added to make leaks detectable. The odorant is typically a sulfur-containing compound, such as ethyl mercaptan, that gives a strong, unmistakable smell even at very low concentrations, alerting people quickly to a leak and enhancing safety. Dye or colorant would not reliably signal a leak by smell and could be ineffective in actual detection, while a lubricant would contaminate the gas and equipment, serving no purpose for leak detection.