Frequent Questions: Radiation Sources

View frequently asked questions and answers related to radiation sources by topic.

On this page:

• Consumer Products
• Granite
• Non-Ionizing Radiation
• Cell Phones
• Nuclear Power Plants
• Naturally Occurring Radioactive Materials

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Consumer Products

What is food irradiation?

Food irradiation is a process that uses radiation to control pests (e.g., microbes and insects) in food and prevent spoilage. Food irradiation is similar to pasteurizing milk and canning fruits or vegetables as it can make food safer for consumption. Irradiation does not make the food radioactive, nor does it change the taste, texture, or appearance of the food. During irradiation, gamma rays, x-rays, or high-energy electrons pass through the food, destroying or inactivating bacteria and viruses that cause foodborne illness.

Irradiated food is considered safe by the Food and Drug Administration (FDA), the World Health Organization (WHO), the Centers for Disease Control and Prevention (CDC), and the U.S. Department of Agriculture (USDA). FDA is responsible for the regulation of food irradiation. For more information, visit:

• Food and Drug Administration (FDA) page: Food Irradiation: What You Need to Know
• Centers for Disease Control (CDC) page: Food Irradiation

What federal standards address radioactivity in food?

The U.S. Food and Drug Administration (FDA) sets standards for radioactivity in food. FDA sets derived intervention levels (DILs) – concentrations of radioactivity in food – which are used to determine whether domestic food in interstate commerce or imported food presents a safety concern. FDA determines whether protective actions are necessary on a case-by-case basis.

For more information, see Radionuclides in Imported Foods - Levels of Concern on FDA.gov. 

The EPA is responsible for regulating radioactive contaminants in drinking water. For more information, see Radionuclides Rule.

Is there radioactivity in food?

Food may contain different types and amounts of naturally-occurring radioactive materials. For example, a small fraction (0.012%) of potassium in foods is radioactive. Additionally, naturally-occurring radioactive materials in the soil can transfer to crops, and fish and shellfish can take up radioactivity from water or sediments. Generally, food in the home contains too little radioactivity to be detected and does not pose a significant health risk.

For information about food recalls and alerts in the United States, please visit U.S. Food Safety: Recalls and Alerts on FDA.gov.

Is labeling required for radiation-emitting consumer products?

Labeling is required for electronic products that emit ionizing radiation either by design (e.g., x-ray equipment) or as a consequence of operation (e.g., old cathode ray tube televisions).

No labeling is required for products that emit radiation due to decay of a radioactive element or isotope (e.g., ionization type smoke detectors).

For more information, see the Food and Drug Administration (FDA) page on Labeling Requirements for Radiation Emitting Devices and Products.

Are imported products screened for radiation hazards?

U.S. Customs and Border Protection (CBP) is the federal agency tasked with screening imported products for radiation hazards. You can find information about the CBP screening of cargo for radiation in the Agency's report “Non-Intrusive Inspection Systems & Radiation Detection Equipment FY 2015 Accomplishments.

Who monitors radioactivity in domestic and imported foods?

The Food and Drug Administration (FDA) is the federal agency tasked with monitoring food for radioactivity. You can find information about testing food for radiation by visiting Public Health Focus - Radiation Safety on FDA.gov. For information about food recalls and alerts in the United States, please visit U.S. Food Safety: Recalls and Alerts on FDA.gov. 

What kinds of consumer products contain radioactive materials?

A variety of consumer products contain radioactive materials. In some, the radioactive material is a working part of the product. In others, radiation is present because some component contains naturally-occurring radioactive materials.

Consumer products with radioactive components or emissions:

• Smoke detectors: most smoke detectors available for home use contain americium-241, a radioactive element. Unless tampered with, smoke detectors pose little to no health risk; a smoke detector’s ability to save lives far outweighs the health risks from the radioactive materials. For more information on smoke detectors, visit Americium in Ionization Smoke Detectors.
• Clocks and watches: some luminous watches and clocks contain a small quantity of hydrogen-3 (tritium) or promethium-147. Older watches and clocks (made before 1970) may contain radium-226 paint on dials and numbers to make them visible in the dark. Avoid opening these items because the radium could flake off and be ingested or inhaled. Learn more about tritium and radium on the Radionuclides webpage.
• Older camera lenses: some camera lenses from the 1950s-1970s incorporated thorium into the glass, allowing for a high refractive index while maintaining a low dispersion. The health risk from using older camera lenses is low; the radiation received when using a thoriated lens camera is approximately equal to natural background.
• Gas lantern mantles: older, and some imported, gas lantern mantles generate light by heating thorium (primarily thorium-232). Unless gas lantern mantels are used as the primary light source, radiation exposure from thorium lantern mantles is not considered to have significant health impacts.
• Ceramics: ceramic materials such as tiles and pottery may contain elevated levels of naturally-occurring uranium, thorium, and/or potassium. In many cases, the activity is concentrated in the glaze. Unless there is a large quantity of the material, the amount of radioactivity in these products is unlikely to be greater than natural background levels. However, some older dishware (e.g., pre-1972 Fiesta®ware) can have radioactivity exceeding background levels; to minimize health risks, you may not want to use these pieces for eating or drinking.
• Glass: glassware, especially antique glassware with a yellow or greenish color, can contain easily detectable quantities of uranium. Such uranium-containing glass is often referred to as canary or vaseline glass. In part, collectors like uranium glass for the attractive glow that is produced when the glass is exposed to a black light. Even ordinary glass can contain high-enough levels of potassium-40 or thorium-232 to be detectable with a survey instrument. However, the radiation received when using glassware – even canary or vaseline glass – is unlikely to exceed background radiation levels.
• Fertilizer: Commercial fertilizers are designed to provide varying levels of potassium, phosphorous, and nitrogen to support plant growth. Such fertilizers can be measurably radioactive for two reasons: potassium is naturally radioactive, and the phosphorous can be derived from phosphate ore that contains elevated levels of uranium. Learn more about Radioactive Material From Fertilizer Production.
• EXIT signs: Some EXIT signs contain the radioactive gas called tritium, allowing them to glow in the dark without electricity or batteries. The tritium used in EXIT signs gives off low-level beta radiation, causing a light-emitting compound to glow. Tritium EXIT signs do not pose a direct health hazard, as the beta radiation can be stopped by a sheet of paper or clothing. However, tritium EXIT signs must not be disposed of in normal trash. For more information on tritium EXIT signs, see the Nuclear Regulatory Commission’s page on tritium EXIT signs.

Learn more about consumer products that contain radiation on RadTown's Sources of Radiation in Consumer Products webpage.

For more information on consumer products that contain technologically enhanced naturally occurring radioactive material (TENORM), visit EPA’s TENORM webpage.

Are there regulations concerning radiation emissions from power lines?

There are no U.S. Federal standards limiting residential or occupational exposure to electric and magnetic fields (EMF) from power lines. However, some states have set standards for transmission line fields.  Along with more information on EMFs, the National Institute of Environmental Health Sciences' EMF Q&A pamphlet (PDF)( 11.45 MB) provides information about state standards.

Additional Information about EMFs can be found at:
•    RadTown USA, Electric and Magnetic Fields from Power Lines (EPA)
•    The World Heath Organization (WHO)
•    Occupational Heath and Safety Administration (OSHA)

Granite

Are granite countertops radioactive? Are the levels dangerous?

While granite and other decorative stone can contain some trace natural radioactivity, granite countertops are not considered to be a key contributor to radiation in the average home.

Radioactive minerals in the granite can decay into radon – a colorless, odorless, radioactive gas – which may be released from the surface of the granite over time. However the minerals may trap radon within their crystals, the granite is not porous, and exposed surfaces are treated with sealant. This makes it harder for the radon escape from the granite than from more porous stones such as sandstone. 

While radon gas and radiation emission levels attributable to granite are not typically high, there are simply too many variables to generalize about the emissions from granite countertops. However, high levels of radon in the home (from all possible sources) is a health concern because it can cause lung cancer. The Surgeon General and the EPA recommend testing for radon and reducing radon in homes that have high levels.

For more information on granite, see Radon and Granite Countertops and Radiation.

Can I test my granite countertops for radiation?

At this time, one generally accepted radiation testing protocol for countertops does not exist, and neither imported nor domestic granite products require radiation testing.

Radiation concentrations can only be measured using multiple portable instruments or with laboratory equipment. These instruments and equipment require a knowledgeable and trained user and proper instrument calibration. For information about local radiation experts, visit the Conference of Radiation Control Program Directors' (CRCPD) webpage for state radiation protection program contacts.

Although not specifically designed or intended for measuring radon emissions from countertops, do-it-yourself home radon test kits are available through retail outlets and online. If you are concerned about the radon level in your home, purchase a test kit and use as instructed. The Surgeon General and EPA recommend testing for radon and reducing radon in homes that have high levels. For more information on radon testing, visit Find a Radon Test Kit or Measurement and Mitigation Professional.

What advice does the EPA have about radon for consumers who have granite countertops?

EPA believes the principal source of radiation in homes is not granite countertops, but naturally-occurring radon that seeps into buildings from the ground. While natural rocks such as granite may emit radiation and radon gas, the levels attributable to such sources are not typically high. If you are concerned about radon levels in your home, you should first test the air in your home to determine the radon level. For more information, see Find a Radon Test Kit or Measurement and Mitigation Professional.

Are there regulations about radiation in granite countertops?

There are currently no regulations concerning radiation levels in countertops.

For more information, visit Granite Countertops and Radiation.

Non-Ionizing Radiation

Where can I find information about living near a cell phone tower?

The Federal Communications Commission (FCC) regulates systems such as cell phone towers. Exposure levels from cell phone towers must comply with the FCC's radiofrequency (RF) radiation exposure guidelines, which were developed to protect the public from RF-related health risks.  You can find more information about cell phone tower siting on the FCC Tower and Antenna Siting Issues page. 

Where can I get information about electromagnetic radiation from smart meters?

EPA sets protective limits on the radioactivity in soil, water and air that comes from human use of radioactive elements such as uranium.

Smart meters use radiofrequency radiation (RF). The U.S. Federal Communications Commission (FCC) sets exposure limits for RF radiation. FCC works with other federal health and safety agencies to monitor and investigate issues related to RF exposure. To learn more, please visit: Wireless Devices and Health Concerns.

How is the EPA involved with the regulation and safety of nuclear power plants?

The EPA's role in nuclear power generation is to set public health and environmental radiation protection standards. To learn more, please visit Environmental Radiation Protection Standards for Nuclear Power Operations (40 CFR Part 190). The Nuclear Regulatory Commission (NRC) is responsible for licensing facilities, commercial use of nuclear materials, facility inspection and the creation of standards and regulations for nuclear power plant safety. For more information on the NRC’s role, please visit Nuclear Security and Safeguards.

Where can I get information about electric and magnetic fields from power lines?

EPA does not regulate or set standards for power lines.

EPA sets protective limits on the radioactivity in soil, water and air that comes from human use of radioactive elements such as uranium. The transmission of electricity can generate electric and magnetic fields.

There are no U.S. federal standards limiting residential or occupational exposure to electric and magnetic fields (EMF) from power lines.

For links to more information, please visit Radiation Resources Outside of EPA.

Cell Phones

Where can I get information about electromagnetic radiation from cell phones?

EPA sets protective limits on ionizing radiation in the environment resulting from human use of radioactive elements such as uranium. However, cell phones use radiofrequency radiation (RF), which is a type of non-ionizing radiation. The U.S. Federal Communications Commission (FCC) sets exposure limits for RF radiation. FCC works with other federal health and safety agencies to monitor and investigate issues related to RF exposure. To learn more, please visit: Wireless Devices and Health Concerns.

The latest wireless technology is called 5G, which stands for fifth-generation. For information on 5G and health, visit the World Health Organization (WHO) webpage Radiation: 5G mobile networks and health.

Where can I find information about cell phone safety concerns?

Scientific opinions vary regarding risks associated with radiofrequency (RF) radiation exposure from cell phone use. While some studies have shown a correlation between the occurrence of certain adverse health effects and long-term use, a definitive cause and effect relationship has not been established.

The Federal Communications Commission (FCC) has adopted exposure limits to RF energy with which all cell phones legally sold in the United States must comply.  These limits are expressed in Specific Absorption Rate (SAR), which is a measure of the amount of RF energy absorbed by the body while using a mobile phone. 

For more information, please visit the FCC Wireless Devices Health Concerns Consumer Facts webpage and the Food and Drug Administration's (FDA) Cell Phones webpage. The FDA is responsible for making available scientific information on the nature and extent of the hazards and control of electronic product radiation, including from cell phones.

Nuclear Power Plants

What does the EPA do if there is a nuclear power plant accident?

The EPA prepares for, and responds to, emergencies involving radioactive materials. Depending on the location and nature of the incident, the EPA may support local responders or may assume primary authority for response in certain instances. The exact actions the EPA takes during an emergency depends on a number of factors. In any event, the EPA has personnel and equipment to protect human health and the environment during a radiological emergency. For more information, see Radiological Emergency Response. 

Other federal agencies who might play a role in a nuclear power plant accident include:

• U.S. Nuclear Regulatory Commission
• U.S. Department of Defense
• U.S. Department of Energy
• U.S. Department of Homeland Security

Where can I get information about a specific nuclear power plant?

EPA sets environmental standards that apply to members of the public outside nuclear facilities. The U.S. Nuclear Regulatory Commission (NRC) licenses and oversees nuclear power plants. 

For more information, please visit Nuclear Reactors on NRC.gov.

Naturally Occurring Radioactive Materials

What is radon gas? Is it dangerous?

Radon is a naturally-occurring radioactive gas that can cause lung cancer. Radon gas is inert, colorless, odorless and occurs naturally in the atmosphere in trace amounts. Outdoors, radon disperses rapidly and, generally, is not a health issue. Most radon exposure occurs inside homes, schools and workplaces. Radon gas becomes trapped indoors after it enters buildings through cracks and other holes in the foundation. Indoor radon can be controlled and managed with proven, cost-effective techniques.

Breathing radon over time increases your risk of lung cancer. Radon is the second leading cause of lung cancer in the United States. Nationally, the EPA estimates that about 21,000 people die each year from radon-related lung cancer. Only smoking causes more lung cancer deaths.

You can take steps to reduce and control the amount of radon in your home. Testing is the only way to determine radon levels. Have your home tested, either by a professional or with a do-it-yourself home test kit. If radon levels are high, contact a certified radon service professional to fix your home. EPA guidance suggests mitigating if levels are at or above 148 Becquerels/meter³ (4 picocuries/liter). Usually, radon problems are fixed using an underground ventilation system or by increasing the rate of air changes in the building.

For more information about indoor air quality and the health risk of radon, visit Health Risk of Radon.

Where does radon gas come from?

Radon comes from the breakdown of naturally-occurring radioactive elements (such as uranium and thorium) in soils and rocks. As part of the radioactive decay process, radon gas is produced. The gas moves up through the soil to the surface, where it can enter homes, schools and the workplace through cracks and other holes in the foundation. In some cases, radon can enter buildings through well water and come from building materials. Any home can have a radon problem – old or new homes, well-sealed or drafty homes, and homes with or without basements. 

For more information about radon in your home, visit the EPA's Radon web area.

What is background radiation? Is background radiation a risk to me and my family?

Natural background radiation is all around us. Background radiation varies from place to place and over time, depending on the amount of naturally-occurring radioactive elements in soil, water and air. Weather conditions also affect radiation levels, as snow cover may shield these elements, and radioactive particulates can wash out of the air during rain storms. Cosmic radiation from the sun, our galaxy, and beyond is constantly around us and contributes to natural background radiation. Altitude and latitude can also influence the level of background radiation at any one site.

All rocks and soils contain some trace amount of natural radioactivity and can sometimes be ingested or inhaled if disturbed. Radon is a gas that can concentrate indoors and be inhaled, along with its decay products. We can also ingest radioactivity from the food we eat and the water we drink. 

A number of factors determine the annual dose you and your family receive from background radiation. The following chart shows the percentage of background radiation dose received annually from various natural sources.

To estimate your personal yearly radiation dose from the most significant sources of ionizing radiation, please visit Calculate your Radiation Dose.

For more information on background radiation, visit Radiation Sources and Doses.

For more information on radon and how it may affect you and your family, visit the EPA's Radon web area.

Where can I find more information about radon in my home?

Visit the Radon web area to learn more about the health effects of radon exposure and the steps you can take to reduce radon in your home. 

To find a state radon program contact, visit EPA Map of Radon Zones.