New York City was the scene of a puzzling mystery Monday. An unidentified gas-like odor made its way across Manhattan and parts of New Jersey and resulted in some building evacuations and mass transit interruptions.
New York City Mayor Mike Bloomberg was quick to assure the city that there was no indication the air was unsafe to breathe. Russ Knocke, spokesperson for the Department of Homeland Security, added his assurances that the department had no reason to believe that this was an act of terrorism.
How can you protect your family from the health threat posed by leaking gas entering your home from outside? The most important thing you can do is to learn what to look for so that you can react quickly and appropriately.
The first type of gas to watch out for is natural gas. Mayor Bloomberg said that sensors the city was using to monitor the situation did not show any high concentration of natural gas. However, natural gas is commonplace in our homes because we use it to cook our food and heat our houses.
For the most part, natural gas is safe and efficient. The component of natural gas that makes it dangerous is methane, which is extremely flammable. A natural gas leak can cause a fire or an explosion. It's not easy to detect a natural gas leak because methane, and the carbon monoxide that it releases, is odorless, tasteless and colorless.
Many gas companies add mercapton or some other sulfide-based substance to natural gas. This is what gives it that "rotten egg" smell and makes leaks easier to detect. In addition to the mercapton smell, you can also detect a natural gas leak if there are streaks of carbon or soot on your gas appliances, there is no draft in your chimney, you see a great deal of rust on flue pipes, moisture collects on windows or walls in the room in which your furnace is located, and there is rust on exterior vent pipes.
If you suspect a natural gas leak in your home, take your family and get out immediately. Don’t wait to phone the gas company, or even to turn the lights off. Don't unplug appliances, because any electrical spark can cause an explosion if there is a natural gas leak.
As soon as you are safely outside, call the gas company from your cell phone or from a neighbor’s house and let them handle the situation.
Don’t go back into the house until the gas company tells you it is safe to do so.
The second type of gas to be mindful of is carbon monoxide (CO). Your bloodstream absorbs this odorless gas quickly because red blood cells pick it up at a faster pace than they do oxygen. If a significant amount of CO is present in the air, your body may start replacing the oxygen in your blood with CO. This prevents oxygen from getting into the body, which results in suffocation and eventually leads to death.
Low-level exposure to carbon monoxide shouldn't be a problem. Being exposed to high levels can result in flu-like symptoms, including:
-- Dizziness
-- Nausea
-- Headache
-- Fatigue
-- Irregular breathing
Excessively high levels of exposure can lead to loss of consciousness or even death.
If the victim has been exposed to low levels of CO, get him/her into fresh air immediately and the problem should reverse itself.
If the victim is unconscious because of high-level exposure, get him/her into fresh air at once and call 911. Give the victim mouth-to-mouth resuscitation until medical help arrives.
The best way to protect your family from CO poisoning is to install a CO detector in your home.
There is a wide selection of CO detectors available with various features. Some can be installed just like smoke detectors. Others require a technician to connect the detector to your home security system.
Having a CO detector in your home will give your family the time they need to escape without injury.
The third gas to be concerned about is radon. It’s a cancer-causing, radioactive gas. According to EPA's 2003 Assessment of Risks from Radon in Homes, radon is estimated to cause about 21,000 lung cancer deaths per year.
Only smoking causes more deaths from lung cancer. Like the other two gases mentioned in this article, radon is odorless, colorless and tasteless. Testing is the only way to know if your home is at risk from radon.
The Environmental Protection Agency and the Surgeon General recommend testing all homes below the third floor for radon. Testing is easy and inexpensive. There are many kinds of "do-it-yourself" radon test kits on the market. If you prefer, you can hire a qualified tester to do the testing for you. Contact your state radon office to get a list of qualified testers.
For more information, log on to www.epa.gov/radon/radontest.html. January is National Radon Action Month. Why not celebrate by getting your home tested for radon. It may turn out to be the best celebration of your life!
Fox News Health contributor Maria Esposito contributed to this report.

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Dr. Manny Alvarez is the managing editor of health news at FOXNews.com, and is a regular medical contributor on the FOX News Channel. He is chairman of the Department of Obstetrics and Gynecology and Reproductive Science at Hackensack University Medical Center in New Jersey. Additionally, Alvarez is Adjunct Professor of Obstetrics and Gynecology at New York University School of Medicine in New York City.

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Dr. Manny Alvarez serves as Fox News Channel's Senior Managing Editor for Health News. Prior to this position, Alvarez was a FNC medical contributor. Click here more information on Dr. Manny's work with Hackensack University Medical Center. Visit AskDrManny.com for more.