Radiation Exposure and Preparation

According to the Occupational Safety and Health Administration (OSHA), there are two types of radiation: non-ionizing and ionizing. Non-ionizing radiation comes from electromagnetic radiation, from extremely low frequency to ultraviolet. Although radiation can sound alarming, most everyday exposures occur at low levels that pose minimal health risk; understanding dose and context helps determine when exposure becomes significant. OSHA defines the most common form of electromagnetic radiation as sunshine. Exposure can also be generated from power lines, electrical wiring, and electrical equipment. In addition, radiofrequency and microwave radiation can originate from “radios, cellular phones, high frequency welders, induction heaters, communications transmitters, radar transmitters, and ion implant equipment” Lasers can also cause radiation exposure, with the most common damage occurring in the eyes, skin, and tissues.

Ionizing radiation is particulate or electromagnetic and can be natural or created. One form of natural ionizing radiation is radon. Radon is an odorless, colorless radioactive gas that results from the natural decay of uranium and radium in rocks and soil. Radon is found in every state, and nearly one in fifteen homes is affected by high levels in the United States. Prolonged radon exposure can damage lung tissue and increase the risk of developing lung cancer.

Importantly, the level of risk from any radiation exposure depends on several factors, including the dose, the type of radiation, the duration and rate of exposure, and an individual’s age and overall health, meaning risk is not uniform across situations.

In the United States, natural radiation exposure is estimated to be approximately three millisieverts, or mSv, per year. Fortunately, the cells in our bodies are extremely efficient at repairing damage caused by everyday ionizing radiation exposure.

Radon can be found in any type of building. Inexpensive test kits are available for purchase to evaluate the level of radon in the home. Radon is present in nearly all air, and everyone breathes in radon every day, typically at very low levels. However, people exposed to consistently high levels of radon have an increased risk of developing lung cancer.

Most homes that test positive for radon fall within low to moderate ranges, and simple mitigation methods can significantly reduce exposure. Anything exceeding four picocuries per liter of air, or pCi/L, should be reduced by improving ventilation or by equipment that can be installed by radon mitigation professionals, as necessary. Radon levels may be higher in homes that are tightly sealed or built on soil containing uranium, thorium, or radium. Because radon levels fluctuate over time, long-term testing provides a more accurate understanding of household exposure.

Another form of natural ionizing radiation comes from air travel, through cosmic radiation. The amount of exposure depends on the length of travel, latitude, and altitude; for example, traveling from coast to coast across the United States would result in less radiation exposure than a chest X-ray and is considered very low-risk. A round-trip flight from Los Angeles to New York results in an approximate dose of 0.037 mSv, which is considered extremely low compared to medical imaging or high-altitude occupational exposures. Therefore, the health risk of ionizing radiation during commercial air travel or flight crew duty is relatively low. These levels are unlikely to affect human health.

Pregnancies are especially at risk of exposure to ionizing radiation due to the rapid cell growth that occurs during the early stages. According to Copeland and Friedberg (2021), “Irradiation in the period from three weeks after conception until the end of pregnancy may cause deterministic and stochastic effects in a liveborn child.” Risk to pregnancy is dependent on both radiation dose and the stage of pregnancy. The embryo or fetus is most susceptible during the first trimester. According to the National Institutes of Health, fetal radiation doses below fifty milligrays, or mGy, are considered safe and are not expected to cause harm. This highlights that radiation risk during pregnancy is dose- and timing-dependent. Essentially, the womb provides little additional protection from the outside world, so avoiding exposure to such risks is important during pregnancy. The Mayo Clinic advises that air travel is generally safe during pregnancy, but recommends that pilots or flight crew talk to a healthcare provider about the risk of prolonged radiation exposure.

Approximately ninety-nine percent of individuals would not develop cancer as a result of a one-time exposure of one hundred mSv. At this dose level, it is extremely difficult to distinguish any radiation-related cancers from the cancers that already occur naturally, given that about forty percent of U.S. adults will be diagnosed with cancer at some point in their lives. This helps illustrate that not all radiation doses pose the same level of risk.

Exposure to other forms of created ionizing radiation can be a cause for emergency, whether the cause is deliberate or accidental.

OSHA notes that “accidental causes include:

• Releases from a fixed nuclear facility (e.g., a power plant or nuclear reactor).
• Releases from non-nuclear facilities (e.g., laboratories and hospitals using radioactive materials).
• Lost, found, or orphan (i.e., no longer under proper control) sources of radioactive material (e.g., nuclear fuel sources, medical imaging devices).
• Transportation incidents.
• Nuclear weapons accidents.

Deliberate causes include:

• Improvised nuclear or radiological dispersal devices […].
• Sabotage or intentional releases at a fixed nuclear facility.
• Nuclear attacks by other nations (nuclear warfare), either on the United States or elsewhere.”

Although these scenarios can be hazardous, they are rare, and emergency guidance focuses on minimizing dose and exposure in the unlikely event they occur.

Even in emergency scenarios, the actual level of danger varies based on proximity to the source, shielding, and the amount of radiation absorbed. Risk is dependent on context rather than exposure alone.

In order to mitigate risk during such emergencies, CDC recommends getting inside, staying inside, and staying tuned.

Get Inside: Find the nearest building and move to the innermost room away from any windows. Once inside, remove any clothing exposed to the radiation and wash the body thoroughly with soap and water, focusing on exposed areas. If any pets were exposed, bring them in, gently brush particulate from their coat, and wash their fur with soap and water. Seal exposed clothing in garbage bags.

Stay Inside: Shelter in place for at least twenty-four hours. Turn off equipment that brings in air from the outside, and keep windows, doors, and fireplace dampers closed.

Stay Tuned: Listen for additional information from experts through radio, TV, or other technologies.

Ready.gov offers guidance on staying safe during a radiation emergency. Preparing ahead is always recommended for any disaster management, but it is essential during a radiation emergency.

The Federal Emergency Management Agency mobile application is free and available for download. The application provides real-time emergency alerts, emergency shelter locations, and preparation materials for common hazards.

References

CDC. 2024. “Facts About Radiation from Air Travel.” https://www.cdc.gov/radiation-health/data-research/facts-stats/air-travel.html

CDC. 2024. “What to Do in Radiation Emergencies.” https://www.cdc.gov/radiation-emergencies/response/

Copeland, Kyle, and Wallace Friedberg. 2021. Ionizing Radiation and Radiation Safety in Aerospace Environments. Civil Aerospace Medical Institute, Federal Aviation Administration. https://www.faa.gov/sites/faa.gov/files/data_research/research/med_humanfacs/aeromedical/202108.pdf

FEMA. n.d. “Mobile Products.” https://www.fema.gov/about/news-multimedia/mobile-products

Mayo Clinic. n.d. “Pregnancy Week By Week: Is it Safe to Fly During Pregnancy?” https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/expert-answers/air-travel-during-pregnancy/faq-20058087

OSHA. n.d. “Radiation Emergency Preparedness and Response.” https://www.osha.gov/emergency-preparedness/radiation/background

OSHA. n.d. “Laser Hazards.” https://www.osha.gov/laser-hazards

Ready.gov. n.d. “Radiation Emergencies.” https://www.ready.gov/radiation

U.S. Environmental Protection Agency. n.d. “Radon in Homes, Schools and Buildings.” https://www.epa.gov/radtown/radon-homes-schools-and-buildings