Environmental Hazards

Molds are part of the natural environment. Outdoors, molds play a part in nature by breaking down dead organic matter such as fallen leaves and dead trees, but indoors, mold growth should be avoided. Molds reproduce by means of tiny spores; the spores are invisible to the naked eye and float through outdoor and indoor air. Mold may begin growing indoors when mold spores land on surfaces that are wet. There are many types of mold, and none of them will grow without water or moisture.

Molds are usually not a problem indoors, unless mold spores land on a wet or damp spot and begin growing. Molds have the potential to cause health problems. Molds produce allergens, irritants, and in some cases, potentially toxic substances.

Allergic reactions to mold are common and include hay fever-type symptoms, such as sneezing, runny nose, red eyes, and skin rash. Molds can also cause asthma attacks in people with asthma who are allergic to mold.

How do I get rid of mold?

It is impossible to get rid of all mold and mold spores indoors, but indoor mold growth can be controlled by controlling moisture indoors. If there is mold growth in your home, you must clean up the mold and also fix the water problem. If you clean up the mold, but don't fix the water problem, the mold problem most likely will return.

If the moldy area is less than about 10 square feet, you can probably handle the job yourself. However:

If there has been a lot of water damage, and/or mold growth covers more than 10 square feet, consult the EPA's Mold Remediation in Schools and Commercial Buildings. Although focused on schools and commercial buildings, this document is applicable to other building types.

If you choose to hire a contractor (or other professional service provider) to do the cleanup, make sure the contractor has experience cleaning up mold. Check references and ask the contractor to follow the recommendations in EPA's Mold Remediation in Schools and Commercial Buildings, or the guidelines of the American Conference of Governmental Industrial Hygienists.

If you suspect that the heating/ventilation/air conditioning (HVAC) system may be contaminated with mold, consult the EPA's Should You Have the Air Ducts in Your Home Cleaned? before taking further action. Do not run the HVAC system if you know or suspect that it is contaminated with mold - it could spread mold throughout your home.

If the water and/or mold damage was caused by sewage or other contaminated water, then call in a professional who has experience cleaning and fixing buildings damaged by contaminated water.

If you have health concerns, consult a health professional before starting cleanup.

For more information, read the EPA's A Brief Guide to Mold, Moisture, and Your Home.

The above information is provided as a public service by the Environmental Protection Agency for educational purposes.

Radon is a naturally occurring radioactive gas found in soils, rock, and water throughout the U.S. Radon causes lung cancer, and is a threat to health because it tends to collect in homes, sometimes to very high concentrations.

Almost all risk from radon comes from breathing air with radon and its decay products. Radon decay products cause lung cancer.

There is no safe level of radon - any exposure poses some risk of cancer. In two 1999 reports, the National Academy of Sciences (NAS) concluded after an exhaustive review that radon in indoor air is the second leading cause of lung cancer in the U.S. after cigarette smoking. The NAS estimated that 15,000-22,000 Americans die every year from radon-related lung cancer.

You cannot see, feel, smell, or taste radon. Testing your home is the only way to know if you and your family are at risk from radon. EPA and the Surgeon General recommend testing for radon in all rooms below the third floor.

Radon testing is inexpensive and easy--it should only take a few minutes of your time. Millions of Americans have already tested their homes for radon. Various low-cost, do-it-yourself test kits are available through the mail and in hardware stores and other retail outlets. You can also hire a trained contractor to do the testing for you.

The first step is to test your home for radon, and have it fixed if it is at or above EPA's Action Level of 4 picocuries per liter. You may want to take action if the levels are in the range of 2-4 picocuries per liter. Generally, levels can be brought below 2 pCi/l fairly simply.

The best method for reducing radon in your home will depend on how radon enters your home and the design of your home. For example, sealing cracks in floors and walls may help to reduce radon. There are also systems that remove radon from the crawl space or from beneath the concrete floor or basement slab that are effective at keeping radon from entering your home. These systems are simple and don't require major changes to your home. Other methods may be necessary.

People who have private wells should test their well water to ensure that radon levels meet EPA's most recently proposed standard.

For more information, read the EPA's A Citizen's Guide to Radon.

The above information is provided as a public service by the Environmental Protection Agency for educational purposes.