This public health statement tells you about radon and the effects of exposure to it.
The Environmental Protection Agency (EPA) identifies the most serious hazardous waste sites in the nation. These sites are then placed on the National Priorities List (NPL) and are targeted for long-term federal clean-up activities. The presence of radon at any site could be a consequence of its natural occurrence in the environment; its production from substances in anthropogenic hazardous waste; or both. These sites may be sources of exposure and exposure to this substance may be harmful.
When a substance is released from a large area, such as an industrial plant, or from a container, such as a drum or bottle, it enters the environment. This release does not always lead to exposure. You are exposed to a substance when you come in contact with it. You may be exposed by breathing, eating, or drinking the substance, or by skin contact. External exposure to radiation may occur from natural or man-made sources. Radon is a naturally-occurring radioactive gas that changes into other radioactive substances, called progeny. Since radon and its progeny are present together in rock, soil, water, air, and construction materials, you will be exposed to the low-level radiation they give off just by being near them. Naturally occurring sources of radiation include radon and other radioactive elements in air, water, soil, or building materials, as well as cosmic radiation from space. Man-made radioactive materials are found in consumer products, industrial equipment, nuclear medicine patients, and to a smaller extent from atomic bomb fallout, hospital waste, and nuclear reactors.
The results of the 1992 EPA National Residential Radon Survey estimated that 1 in 15 homes had an elevated radon level (i.e., a level at or above the EPA action level of 4 picocuries per liter of air). At the time, an estimated 5.8 million homes had an elevated radon level. The source of radon in homes is from naturally occurring (geologic) sources.
When you are exposed to radon many factors will determine whether you will be harmed. These factors include the dose (how much), the duration (how long), and how you come in contact with it. You must also consider any other chemicals you are exposed to and your age, sex, diet, family traits, lifestyle, and state of health.