Q: Should homeowners consider the radon threat a false alarm?

0 Comments | Insight on the News, April 7, 1997 | by Cassandra C. Moore, | Mary Nichols

Yes: Federal officials have overreacted to a minor problem, and tax-payers are paying a high price.

"Call 1-800-RADON!" screamed the billboards in the rail stations. "Radon is a health hazard in your home," proclaimed the Environmental Protection Agency, or EPA, which ran an Ad Council TV spot a few years ago showing children playing in a comfortable middle-class living room who, exposed to radon, suddenly turned into skeletons.

The billboards have faded from view; buffeted by protests, the EPA no longer shows the television clip. It continues to maintain, however, that exposure to radon is dangerous, causing up to 14,000 deaths annually from lung cancer -- a retreat from original estimates of 30,000.

Radon scarcely justifies the alarm. It is odorless, colorless, tasteless, a noble gas in the periodic table of the elements, the byproduct of the decay of uranium. Since uranium is widespread, the gas escapes constantly into the atmosphere. It is moderately soluble, so well water passing through uranium-bearing rocks emits radon upon contact with the air.

Even the EPA will admit that radon itself poses no substantial health risk; but its decay produces a chain of radioactive particles, radon "daughters" or radon "progeny." They in turn decay, releasing alpha particles that can penetrate lung cells, damaging DNA and other cellular components. Humans have the capacity to repair damaged DNA and do so regularly. The agency, however, claims that the ionizing radiation produces irreversible damage that will lead inexorably to lung cancer.

Is the projection realistic? It is based on 50-year-old studies of uranium miners on the Colorado plateau. Developed after World War II, when the concern with nuclear weapons propelled a search for uranium, the mines were "dog holes" -- dusty, poorly ventilated, thick with smoke. The miners themselves smoked, unknowingly increasing the cancer risk. Data were unreliable: levels of exposure, in particular, were uncertain, given the dearth of measurements in the 1940s and 1950s and the questionable value of those that were made, often by the miners themselves.

Radon, however, remained a concern of homeowners in Western Mountain states until 1984 when Stanley Watras, an engineer set off alarm bells by walking into a nuclear plant under construction in Pennsylvania. The radon level in his home was 16 times that permitted in mines; in fact, the house had been built over an abandoned mine. Suddenly it appeared that uranium and radon were widespread; the gas became a concern not only for miners but for householders nationwide. Anxiety rose and with it the burden imposed on homeowners. Suddenly another "spook" had joined asbestos and lead as a toxic specter to be feared.

The EPA's approach fanned the flames. Miners who had inhaled radon showed a high incidence of lung cancer, so it was inferred that radon in the home posed a similar threat, despite much lower concentrations and quite different conditions. A generation later, the EPA still was claiming that "we know more about radon risks than risks from most other cancer-causing substances because estimates are based on studies of cancer in humans (underground miners)." The radon specter was casting a longer shadow.

The agency insists that no level of radon is without risk. Scientists and statisticians generally view such a "linear, no-threshold" hypothesis with skepticism. Regardless, the EPA continues to see its mission as protecting the public from the health risks associated with indoor radon. In 1988, together with the U.S. surgeon general, the agency issued a nationwide health advisory urging that every dwelling in the country be tested for radon, despite the time needed, the costs imposed -- an estimated $10 billion to $20 billion -- and the uncertainty of the results, which can vary with temperature, time of day and season.

What would the tests find? The levels of radioactive decay are measured in picocuries per liter and abbreviated as pCi/l. (The picocurie is one-trillionth of a Curie, itself a measure of radioactive disintegrations per second.) According to the EPA, those houses with levels of four picocuries or higher per liter of air should be remediated -- an expensive process of sealing cracks in basement floors (even though radon can permeate concrete), installing subfloor or subslab ventilation and setting up fans or blowers to move air through the house. The agency has estimated the cost at $1,500 to $3,000 per unit; in reality, the cost can go much higher. Duct units could push the tab to $25,000.

For new housing, the agency and the National Association of Home Builders spent four years establishing mutually acceptable, radon-resistant construction standards for new homes. The standards specify the spreading of gravel under the slab -- already a practice of many contractors -- the use of a polyethylene film on top of the concrete on top of the gravel, the sealing of cracks in the slab and between the edge of the slab and the walls of the foundation. In addition, a 4-inch pipe must be installed running through the house from the gravel through the roof, a standard requiring a wider wall, while the attic must have an electric outlet for use in installing a fan, should the homeowner determine that radon is present and consider ventilation advisable.