Radon - You can't see it. You can't smell it. You can't taste it. Radon, a 'Class A' carcinogen, is the second leading cause of lung cancer. Radon comes from the radioactive breakdown of naturally occurring radium found in most Florida soils. As a gas in the soil, it enters buildings through small openings in the foundation. Since the building can hold the radon similarly to smoke trapped under a glass, indoor radon concentrations can increase to many times that of outdoor levels.

The following article is a commercial downloaded off the Internet on 4-4-97. Numbers, addresses, prices, etc may not be current. This article is for informational purposes only.

What Is Radon?

Radon is an odorless, tasteless and invisible radioactive gas produced from the decay of the element uranium. Uranium is present, usually in trace amounts, in soil and rock containing granite, shale, or phosphate. It may also be present in groundwater that has passed through soil and rock containing uranium and in building materials made from materials containing uranium. On average, about six atoms of radon emerge each second from every square inch of soil.

Radon is found in high concentrations throughout the United States; by no means is radon limited to well publicized "hot spots" (areas with high concentrations of uranium-bearing soil) such as the Reading Prong, which runs through parts of Pennsylvania, New Jersey, and New York.

Why Is Radon Dangerous?

In the atmosphere, radon is harmless because it is diluted. The average radon level outdoors is .2 picocuries per liter (pCi/l) of air or less. (Levels of radon are reported in one of two ways: pCi/l or Working Levels (WL) of radon.) In an enclosed area, radon can build up to a dangerously high level. Extremely high radon levels-hundreds and thousands pCi/l-have been detected in some homes throughout the United States.

Exposure to radon is dangerous because some of radon's decay products revert to a solid form (isotopes of polonium). These radioactive atoms can become lodged in lung tissue, damaging the DNA genetic code of cells. Such damage may lead to lung cancer, though the condition may not develop for years or even decades after exposure. Lung cancer is the only known health risk posed by radon. Radon is attributed to anywhere from 7,000 to 30,000 lung cancer deaths each year.

The higher the radon level and the longer the exposure, the higher the risk of developing radon-induced lung cancer. Breathing in tobacco smoke also increases the risk because the smoke provides another vehicle by which radon can enter the lungs of the smoker and, through second-hand smoke, the nonsmoker as well. Smokers, however, face the greater health risks. Children may be the most vulnerable to radon, possibly facing triple the health risk of adults.

Because radon risk estimates are based on studies of underground miners exposed to varying degrees of radon, scientists are considerably more certain of the risk estimates for radon than they are of risk estimates based solely on animal studies.

In calculating the estimates shown in the following chart, the Environmental Protection Agency made some assumptions about the duration and frequency of radon exposure to which the "community" was subjected. EPA assumed that the community was exposed to the radon level for roughly 70 years and spent 75 percent of its time inside the home from which the radon measurement was taken. Those assumptions should be taken into consideration in assessing one's own personal radon risk.

Also, it should be noted that smokers, who have a much higher chance of radon-induced lung cancer, are factored into EPA's radon risk estimates, which are based upon the average population. (The 1992 edition of EPA's A Citizen's Guide To Radon, What It Is And What To Do About It, will provide a breakdown of the radon risk estimates for smokers and nonsmokers.)

Is Radon A New Problem?

Underground miners have been dying of radon-induced lung cancer for centuries, though radon and lung cancer weren't clearly linked until the 1950s and 1960s.

A curious incident in 1984 grabbed the attention of the scientific community and eventually led to the realization that naturally occurring radon could be a significant health threat inside residential dwellings. In December of that year, an employee of the nuclear power plant in Limerick, Pennsylvania, set off a radiation detector upon entering his work facility. The man's home was subsequently monitored for radiation and found to contain a shockingly elevated level of radon. At 2,700 pCi/l the worker's house contained more than 13 times the level of naturally occurring radon ever expected to be found inside a private residence. The man was actually contaminated with radiation from the radon inside his own home.

Widespread radon testing conducted after this incident revealed that residential radon was a problem national in scope. In September 1988, the Surgeon General recommended that all homes, except residences above the second floor in multi-level buildings, conduct radon screening tests.

How Does Radon Enter A Home?

Radon can seep into a home through dirt floors, cracks and pores in concrete walls and floors, hollow-block walls, joints, drains pipes, and sump pumps. Building supplies made from materials containing uranium are rarely a significant source of residential radon.

What About Radon In Water?

Water is a vehicle by which radon can enter the home. It is not considered harmful to drink water containing radon; the gas becomes a threat only when it is released into the air when faucets are turned on or when water-using appliances are operated.

Contaminated water accounts for a small degree of the radon health problem, increasing the number of radon-induced lung cancer deaths by an estimated 2 to 9 percent per year. On average, about 2 to 5 percent of radon found in homes stems from the water supply serving the home. If a home has been found to contain no measurable radon, there is generally no need to test the home's water supply, according to EPA.

Surface Water Vs. Ground Water

Homes can be supplied with water in one of two ways: surface water or ground water. Surface water does not pose a radon threat because the gas is released into the air before it reaches the home

Ground water that passes through porous soil and rock containing uranium may contain radon. However, the great majority of municipal ground water supplies do not contain a significant amount of radon because the radon is released into the air when the water supply is treated and because radon converts to another form when held in storage.

Most waterborne radon problems occur in homes served by an individual well or a small community ground water system (serving up to about 100 homes) located in areas with a high level of ground radon. Such homeowners may want to consider having their water tested. Radiation Offices in each state can provide sources of further information. Please see the last page of this brochure for phone numbers in U.S. Healthcare's service area.

EPA is in the process of developing a water drinking standard to set a maximum contaminant level for radon.

What Homes Should Test For Radon?

All homes should be tested for radon, except residences above the second floor in multi-level buildings, according to the Surgeon General, the Environmental Protection Agency, the American Lung Association, and the American Medical Association. (It is also recommended [though not required by law] that schools and daycare centers test for radon.)

The only way to know if your home has a radon problem is to test for levels of the substance. If your neighbors have tested and have found no problem, you should still conduct your own test because radon levels can vary greatly from house to house-sometimes even from room to room.

How Is Radon Testing Performed?

This section explains the basics about radon testing methods that are available to the general public. (Professional radon testing services can be employed for a much higher price.) Radon detection kits are relatively inexpensive (starting at about $25) and simple to use, and readily available in hardware stores, grocery stores, and department stores. Once the test is completed, the homeowner mails the device back to the manufacturer for analysis. EPA's Radon Measurement Proficiency Program evaluates companies that make and analyze test kits. It is wise to purchase a test kit from a manufacturer who has completed this program. Usually, this is indicated on the radon detector box.

There are two basic types of radon tests. The short-term is conducted for 2-7 days. The long-term test is usually conducted over a 3-12 month period, but may be limited to as little as 30 days. The most popular commercially available short-term test is the charcoal canister. The most popular commercially available long-term test is the alpha track detector. Both are placed in an appropriate area of the home and left undisturbed until the recommended testing period expires.

Short-Term Vs. Long-Term Tests

Radon can fluctuate substantially over a short period of time. The alpha-track (long-term test), which takes into consideration seasonal variations, yields a measurement that is more representative of annual average radon levels in the home. The charcoal canister (short-term test) is only indicative of the radon measurement for the season during which it is used. It may be said that a short-term test provides a "snap shot" view of a home's radon situation, whereas a long-term test shows the "big picture." In summary, the charcoal canister is the fastest way to find out whether or not radon may be a potential problem, whereas the alpha track is the more accurate measure of a home's overall radon level. Generally, long-term tests cost about double that of short-term tests.

Conducting A Short-Term Test

The charcoal canister should be used only in the cooler months of the year, with the doors and windows closed. During cooler months, the increased difference in indoor/outdoor air pressure creates an environment in which more radon is likely to enter the home. Test results are therefore more reliable (and usually higher).

The device should be placed in the lowest livable area of the home, starting with the basement, if one exists. This is because in closed-house conditions, radon dilutes as it moves upward. Readings taken on the first floor of a structure are usually half those taken in a basement, and they tend to get even lower going farther up in the structure. Testing the lowest livable area in closed-house conditions provides what is likely to be the highest concentration of radon in that structure. All windows and doors should be kept closed for at least 12 hours prior to the start of the test. Windows and doors should remain closed as much as possible throughout the testing period.

Conducting A Long-Term Test

If the homeowner has not already conducted a short-term test, the alpha track detector should be placed in the lowest livable area or potentially livable area. (A crawl space is not a potentially livable area; a basement, even if not used, is a potentially livable area.) If a short-term test has already revealed the presence of radon in the home, follow-up measurements should be made in at least two lived-in areas of the home: for example, the basement, the most lived-in area of the first floor (but not the kitchen), and the second-floor bedroom. The results of these tests should be averaged together. If it is not economical to conduct three follow-up tests, at least one should be performed.

When To Take Action

The EPA currently recommends that homeowners use the short-term screening measurement to test their homes for radon. If the screening test indicates radon levels of 4 pCi/l or more, a follow-up test should be conducted. Based on the follow-up test results, the EPA recommends that action be taken in the following time frames:

• For levels of 4 to 20 pCi/l, the EPA recommends that action should be taken to reduce radon levels as low as possible and retest.
• For levels of 20 to 200 pCi/l, the EPA recommends radon remediation and retest.
• For levels greater than 200 pCi/l, action should be taken now and retest. If this time frame is not possible, a temporary increase in ventilation or relocation to another residence should be considered until a reduction in radon levels can be achieved.

Because there is no known cut-off point at which radon ceases to pose a threat to health, the EPA recommends that all homeowners take action to reduce radon to the lowest level possible, even for those homes with radon levels below 4 pCi/l.

How Can A High Radon Level Be Reduced?

There are two basic methods of reducing indoor radon. The first is sealing cracks and other pathways through which radon can enter the home. This may involve covering exposed areas of earth in basements, storage areas, drains, and crawl spaces with impermeable materials, such as plastic sheet metal, and sealing cracks and openings with mortar or urethane foam. The homeowner may need help from experienced professionals in identifying the trouble spots.

The other method of reducing indoor radon is increasing ventilation so that radon is forced out of the house. Several techniques can be used to achieve this. Considered by many to be the most effective is subslab ventilation in which a PVC pipe is inserted through a floor of the home that touches the soil. That pipe is routed through the wall up into the attic and connected to a fan, which pulls the radon from the soil and expels it into the outside air. The average cost of subslab ventilation is $950.00 and if there is a sump available a subtile ventilation system would be installed at an average cost of $750.00. New home builders are installing this modification (to varying degrees). If done correctly, their efforts can make it easier and more economical for the homeowner to correct a radon problem, should one be detected. The PVC pipe should be capped if it's not connected to a ventilation system; otherwise it could actually promote the entry of radon into the home.

It should be noted that radon contamination in the home cannot lead to radiation contamination of carpets, furnishings, eating utensils, etc.; therefore, there would be no need for a homeowner to replace household objects.

How Can I Find A Radon Contractor?

Contractors specializing in radon remediation can be found through EPA regional offices, state radon offices, Better Business Bureaus, and local Consumer Affairs departments. Since radon reduction is a relatively new line of work, it may be wise to find out how long the contractor has been in business and how many customers have been served by the business.

 

© 1994 U.S. Healthcare®. All rights reserved. The above information was compiled in August 1994 . Please contact your primary care physician for the most recent information about radon.

This medical information has been prepared for your general knowledge by or in consultation with health care professionals. U.S. Healthcare does not recommend the self-management of health problems, nor does U.S. Healthcare promote any particular form of medical treatment. If you have a health concern, you should consult your primary care physician for advice and care appropriate to your specific medical needs.