Why can’t I smell natural gas?

Some factors hinder our ability to smell natural gas, aside from scrubbing, which depletes the odorant level injected into the gas stream. Do you know if you are susceptible?

Odorize Natural Gas

As an odorizer manufacturer, we design systems to inject odorant (the scent) into gas. It’s federally regulated and stipulated that any odorless gas within a distribution or transmission line (exceptions noted in the regulations) must contain odorant at the level of 1/5 the lower explosive limit so that a person with an ordinary sense of smell can detect it.

Factors Affecting Odorant Perception

While we all may think we have a “normal” sense of smell, our ability to perceive odors changes from time to time. Here is a list of several factors that impede a person’s ability to smell:

• Aging – It is natural to experience a loss of smell with aging, especially over 60 years of age.
• Smoking – Smokers regularly experience a severe impairment of the sense of smell, and even when quitting, it may take quite some time to regain the sense fully.
• Health – It is common to experience a temporary loss of smell with colds, allergies, sinusitis, and even nasal polyps. Additionally, damaged nerves from head trauma or surgery can also impair a person’s ability to sense an odor.
• Distractions – When we are distracted by outside stimulation, we may be preoccupied and buffer out sensory information and opt to ignore a smell.
• Odor fatigue – After prolonged exposure to a compound, such as a mercaptan, it is customary to experience olfactory fatigue (adaptation), which is the inability to distinguish particular odors.
• Masking – Masking is not impeding smell; it is covering up one smell with another compound. Some gas companies use masking agents to overpower the mercaptan odor, thus hiding it to help mitigate odor from incidental odorant spills, or while performing maintenance on odorant injection equipment.

We are in the business of putting odorant into a stream of gas so that it smells. It is essential to understand; however, even when we think we have a “normal” sense of smell, it may be impaired from time to time. In these situations, understand that perceiving the rotten egg smell associated with the presence of gas may be harder to detect.

In our next post, we discuss scrubbing and factors that deplete the odorant injected into natural gas so that it may be undetected, creating another safety concern.