Radon - A Short History

Radon has been present in the earth's crust for billions of years. It is produced by the natural disintegration of radium, which is a lustrous, white radioactive element produced by the decay of uranium, and sometimes found in rock or bedrock. Before radon was discovered to be hazardous to human health, homes in the American West were sometimes built with materials contaminated by the radium from uranium mines.

In some rare cases, homes elsewhere were also built from radioactive materials. For example, some homes built in the 1920s in Pennsylvania were found to contain radon-contaminated sand in their plaster, stucco and concrete, The contaminated sand had been furnished free to contractors by a factory which extracted radium 226 from ore in order to treat cancer patients.

Clock faces have also sometimes been painted with radium so that people could see the numbers glow in the dark. Radium is still sometimes used to treat cancer, and it is also still occasionally used in luminous paints and varnishes. Radon gas was discovered to be a product of radium in 1902. Marie Curie won the Nobel Prize in 1911 for her research isolating metallic radium.

According to Parade Magazine, November 4, 1990, a famous story about radon concerns a house in Boyertown. PA lived in, in 1984, by the Stanley Watras family. At that time, Mr. Watras was working as a construction engineer at the Limerick Nuclear Power Generating Station in Pottstown, Pa. One day he visited the plant's radiation-detection section, and when he stepped into it, his radiation levels were so high he blew out the monitor.

A survey showed that every part of his body was contaminated by radiation. This was shocking, especially as he didn't work directly with radiation. He began to wonder whether he'd been exposed to radiation at home. When it became clear that his home was, in fact, contaminated by radon gas, the family moved to a motel, and then rented another house for almost a year.

Meanwhile, the Watras house was found to have 4,400 picocuries of radon per liter (pCi/L) of air in the cellar, 3,200 pCi/L in the living room, and about 1,800 pCi/L in each bedroom. (To put these numbers into context, having 4 picocuries of radon per liter of your indoor air is roughly equivalent to receiving 200 chest x-rays per year.)

According to Parade Magazine, November 4, 1990, the Philadelphia Electric Co. took on the house as an experiment. Contractors sealed and caulked cracks in the basement, and laid air pipes under the concrete foundation of the house, and on top of the soil, to draw radon off.

Then they used fans to further reduce levels of radon gas. These measures reduced the average radon level in the house to 4 picocuries. Stanley Watras began working in the radon mitigation field, and he and his family returned to their original home.