Natural Gas/Propane Gas: Minimizing Potential for Harm

April 2001 (updated 2008)

Nova Scotia is in the process of bringing natural gas onshore and piping it into homes and businesses across the province, and bringing with it many perceived benefits to the province. As long as the supply lasts, it is a relatively clean burning fuel, therefore causing less combustion pollution. It should be less expensive than the coal and oil fuels we have traditionally burned. Also, propane gas equipment that is currently being used can generally be converted to burn natural gas.

Nothing comes without its challenges, however, and natural gas is not an exception. As with propane gas, it is becoming more commonly recognized that there are potential risks to human health from the use of combustion appliances and furnaces. The three main health concerns from natural gas are explosions, exposure to combustion byproducts and exposure to gas leaks.

“… Natural gas has been found to be one of the most important sources of indoor air pollution and sensitizing agents …” says Dr. Gerald Ross, MD, founding Director of the Nova Scotia Environmental Medicine Clinic and Past President of the American Academy of Environmental Medicine.

Dr. T.G. Randolph, MD, writes “… For the chemically sensitive individual this gas may be the worst form of fuel.” Randolph’s clinical studies found that all family members’ health improved, not just the health of chemically sensitive family members, when gas appliances were removed from the home.

Dr. Bill Rea, MD, Chair of the Environmental Health Center, Dallas, adds, “In both Randolph’s and our combined series of 47,000 patients, the most important sources of indoor pollution responsible for generating (environmental) illness were the gas cook stoves, hot water heaters, and furnaces.”

The British medical journal, The Lancet, reported in 1996 that the use of domestic gas appliances, especially gas stoves, was linked to increased asthma, respiratory illness, and impaired lung function, especially in young women. The same study showed that venting the gas stoves did not reduce adverse effects.

The American Journal of Respiratory and Critical Care Medicine (1998; 158:891-895) found “a significant adverse effect of gas stove exposure on respiratory health in children,” more than doubling their risk for respiratory symptoms, including asthma.

By 1994 the Canada Mortgage and Housing Corporation (CMHC) had recommended the replacement of indoor gas appliances and combustion sources with electrical appliances in order to reduce indoor air pollution.

To quote information from the article Gas Attacks, “Natural gas brings harmful chemicals and health hazards into homes through the methane in natural gas itself, as well as with its impurities, contaminants, additives and products of combustion. Natural gas (methane) itself is an asphyxiant which contains impurities and additives, which typically include radon and other radioactive materials, BTEX (benzene, toluene, ethylbenzene and xylene), organometallic compounds such as methylmercury organoarsenic and organolead, mercaptan odorants and other toxins. When natural gas is burned, as in cooking and heating, the chemicals create nitrogen dioxide, carbon monoxide, fine particulates, polycyclicaromatic hydrocarbons, volatile organic compounds (including formaldehyde) and hundreds of other chemicals. Just imagine what you are breathing when you bend over a gas cook stove to stir your food or when you open the oven door. This stuff sticks to your food too, so you eat it as well. It sticks to clothes in gas dryers so you are covering your skin in it. It is lighter than air so it rises up into your living and sleeping areas, concentrating higher up nearer your head. This is one reason why gas is worse than fuel oil which is heavier than air and thus sinks and which is never used in stoves or driers, etc.”

The article goes on to say, “At a recent conference on air quality and childrens’ health sponsored by the Lung Association, much attention was paid to the extreme problems caused by molds. And natural gas turns out to be a strong contributing factor. One of the principal products of combustion of gas is water vapor. When one cooks with gas or burns gas in any way without perfect venting, considerable amounts of moisture are distributed inside the building, enough to be a significant contributor to molds. And the excess moisture provides better conditions for dust mites. And the water vapor is even an insidiously effective transport mechanism for respirable particulate and volatile organic compounds deep into the lungs and thus into the body.

If You Really Must: Best Practices for Gas

Adverse effects of home and water heating with gas can be lessened considerably by putting the furnace and water heater in a separate building downwind of the house with underground connections. Failing this, putting the furnace and water heater in a separate sealed room with an outside air intake into the room and venting the room itself and all appliances up a chimney that extends above the roof line will result in a substantial lessening of harmful effects. Both furnace and water heater should also be state-of-the-art totally sealed units with separate outside air intakes ducted directly into their combustion chambers and forced exhaust via automatic fans. No side venting should ever be allowed, despite claims of gas purveyors. These practices are recommended as best for all combustion appliances indoors and are likely to increase the health of every individual, even if you are not currently aware of any harmful effects. Still it is safest to not have any combustion at all inside the house.”

For generating electricity or as the heating/power supply for large industrial users, gas appears a good choice as compared to coal or oil burning. The important thing is to isolate both the fuel storage tanks and the combustion centre (furnace room) from the main building, so there is little chance of leaks entering the living space.

Some schools and other buildings in the province are being built with geothermal and solar heating/air conditioning. Back-up systems of gas-generated electricity are used. This minimizes fossil fuel use, but uses more efficient, cleaner burning fuel when the main system is not enough.

Environment Canada has programs and grants available to encourage use of renewable energy. Ask for information on residential use of solar or geothermal energy. For commercial buildings there are CBIP (Commercial Building Incentive Program) grants for use of solar panels and solar walls and geothermal heatpumps. There are also grants for meeting assessment criteria for sustainable buildings, such as LEED, GB-Tool 2000 (Green Building Tool) and the C-2000 program for achieving high performance for commercial buildings.

Nova Scotia made a commitment to reduce greenhouse gas emissions to three and a half million metric tons equivalent, which is 16.5% below business as usual, by 2010. Reducing these emissions by using renewable energy will also reduce our dependence on non-renewable petroleum based resources. It will have the added benefits of cleaner air both indoors and outdoors – benefits to both Mother Earth and her inhabitants.

The hazards from possible propane or natural gas explosions still exist, but by keeping the combustion process outside the living space, having no combustion appliances, isolating furnaces, and using other forms of energy as much as possible, we may have found the healthiest combination for now.

– Canadians for A Safe Learning Environment

Gas Attacks. D.Wimberly.
The Healthy School Handbook. Miller. US NEA.
The Healthy Home Handbook: All You Need to Know to Rid Your Home of Health & Safety
Hazards. Warde, John. Toronto: Random House Inc., 1997.
What You Should Know About Combustion Appliances and Indoor Air Pollution. American Lung Association, the US Consumer Product Safety Commission, the US Environmental Protection Agency. 1997.
Natural Gas Leak Warning, Dadd, Debra Lynn. 2008.