Natural gas is combustible and poses some hazards during pest control service

Photo © iStockphoto/Natalja Sidorenko

Natural Gas

Natural gas is a combustible mixture of hydrocarbon gases. While natural gas is formed primarily of methane (70%-90%), it can also include ethane, propane, butane and pentane. It is colorless and odorless in its pure form. Of course, its most important characteristic is that it is combustible, and when burned it gives off a great deal of energy.

It can also be massively explosive when it builds up in an enclosed space and ignites. Everyone has seen the result of those rare natural gas explosions on the evening news.

Since it has no odor of its own, an odorant is added as a warning. The "rotten-egg" smell is mercaptan or a similar sulfur-based compound that can be easily detected by most people at a level well below the flammability level of natural gas.

ALERT: People who have a diminished sense of smell may not be able to smell the warning agent added to natural gas.

Gas leaks can occur inside in or near appliances, or outdoors from buried gas pipes. Common signs of a gas leak include:

• A gas odor (which can best be described as the smell of rotten eggs)
• A blowing or hissing sound
• Water bubbling or being blown into the air at a pond, creek, or river
• Dirt being blown or thrown into the air
• Fire coming from the ground or burning above the ground
• Unusual brown or dead patches of vegetation on or near a pipeline location
• A dry spot in a moist field

If You Smell Natural Gas...

If the gas odor is very weak, most likely a pilot light is out and needs to be relit. Do not relight it yourself (or else you may become liable for any problems later). Notify the tenant, owner, or manager.

If the gas odor is strong, or if you hear a hissing or blowing sound, don’t attempt to locate the problem. Do not do anything that could create a spark. Alert others and leave the building immediately. On the way out:

• Do NOT light a match or a cigarette lighter.
• Do NOT turn any appliance on or off.
• Do NOT use the phone.
• Do NOT turn any electrical switches on or off.
• Do NOT use a flashlight.
• DO leave the door open.
• DO warn others to stay away.

If the property owner is not present, as soon as you are safely away from the building, call your office. Have them notify the fire department and gas company. If you cannot reach your office, call the fire department and gas company yourself.

Remember, do not reenter the building to use the phone.

Old gas stoves may have degraded corrugated gas connectors that can break when moved

Photos © Pinto & Associates

Gas Connectors on Appliances

The biggest hazard to pest control technicians from natural gas comes from pest control work in, around, and under gas appliances, most often stoves but also furnaces, heat pumps, space heaters, water heaters, fireplaces, outdoor gas lights, and dryers.

Be careful if you pull out gas stoves or gas dryers for inspection or treatment. Old, corroded, or too-short corrugated gas connectors can break. The older the connector, the greater the possibility of failure, and in pest control we often work around very old appliances (see top photo).

Connectors on appliances that are frequently pulled out for cleaning or service are under greater stress.

According to the Consumer Product Safety Commission, some of the uncoated brass connectors which were used many years ago have a flaw that can cause a leak, fire, or explosion. These brass connectors haven’t been made for 25 years, but they may still be in use in older homes and apartments. Because of these risks, many companies do not permit technicians to move gas appliances. Check with your supervisor.

In apartments, it’s best to have maintenance staff or an authorized individual pull appliances for you. Note that some state and local regulations require a gas fitter’s or plumber’s license to move any natural gas appliance.

If you’re working around a gas appliance and smell a strong smell of gas or hear a hissing or blowing sound:

1. Follow the rules listed above under "If You Smell Natural Gas..."
2. Close the appliance shut-off valve, if nearby, but only if you can do so without moving the appliance or disturbing the connector.
3. Evacuate everyone from the building immediately, opening doors and windows as you go, and leaving the front door open when you leave.