The History of Radon

Radon is a radioactive element or gas that is released by the decay of radium (a substance found in soil and rock), which is itself produced by the decay of uranium. It is colorless, odorless and tasteless, yet it is known to be very harmful in large concentrations. Although it has been around since the Earth was formed, radon was not discovered until the 20th century.

Dangers Before Discovery

• Scientists determined centuries later that people suffered from exposure to radon in earlier times. Miners in what is now Austria died relatively young as a result of exposure to it. In 1530, the Swiss physician Paracelsus (1493 to 1541) identified their cause of death as a "wasting disease," and German scientist Georg Agricola (1494 to 1555) suggested that mines be ventilated to protect miners.

Discovery

• New Zealand chemist and physicist Ernest Rutherford (1871 to 1937) and German physicist Friedrich Ernst Dorn (1848 to 1916) share credit for discovering radon. In 1900, Dorn published a paper that had been inspired by previous work that Rutherford had done on the radioactive element thorium, verifying that just like thorium, radium emitted a gas. Rutherford confirmed Dorn's work and added that the emission---radon---qualified as a new element, a radioactive one next to others like thorium, radium and uranium.

The Heaviest Gas

• In 1910, chemists Sir William Ramsay (1852 to 1916) and Robert Whytlaw-Gray (1877 to 1958) were able to isolate radon and study its physical properties such as density and weight. They concluded that radon was the heaviest known gas.

Dangers Today

• Radon is known to cause lung cancer at high concentrations. It is a danger not just restricted to mines, as some homes were built in the early 20th century with radon-contaminated materials. The Virginia Department of Health conducted a state-wide survey of 800 homes in 1986, discovering that approximately 12 percent of the homes screened had radon levels above 4 picocuries per liter, which is the recommended action level of the U.S. Environmental Protection Agency (EPA). Radon is also released naturally in the ground and can migrate into your home.

The Watras Family

• An extreme case of the adverse effects of radon is that of the Watras family. Parade Magazine ran a story in 1990 about the family's experience in 1984. Construction engineer Stanley Watras visited the radiation-detection section of the Pottstown, Pennsylvania, plant where he was working, and discovered through a monitor there that he had high radiation levels---so high, he discovered later, that his entire body was contaminated. Since Watras did not work directly with radiation, his contamination was shocking to him. When it was determined that it came from his house at Boyertown, Pennsylvania, Watras moved his family to a motel, then a rented house, for almost a year, while the Philadelphia Electric Company drew radon off from the house. The amount of radon in the Watras home was roughly equivalent to having more than 400,000 chest x-rays per year.