Pilots and Flight Attendants Are Bombarded by Cosmic Radiation—And Getting Deadly Cancers From It

The pilots and flight attendants who help us travel through the sky might be taking on more danger than advertised. Research out today finds that people with these jobs have a noticeably greater risk of dying from certain cancers, likely due to higher exposure levels of cosmic radiation that originate from outer space.

Scientists with Harvard Medical School and others compared death certificate data across hundreds of different occupations. Airline pilots and attendants were significantly more likely to die from cancers related to radiation exposure than other professions, they found, even compared to jobs where people have to intentionally spend time near radiation, like nuclear technologists. This research suggests much more should be done to safeguard these employees from the harmful effects of cosmic rays, particularly in the U.S., the authors say.

“These findings support consideration of occupational radiation protections for aircrew members commensurate with their exposure levels,” they wrote in their paper, published Monday in JAMA Internal Medicine.

Aircrew employees like pilots and flight attendants are already known to have the highest average exposure to ionizing radiation of any occupation in the U.S., with most of this coming from the greater amounts of cosmic rays seen at higher altitudes. Ionizing radiation can trigger the kind of harmful mutations in our cells that can turn them cancerous. However, it’s proven surprisingly difficult to establish whether the added radiation exposure that aircrew employees face actually translates to more cancer deaths, according to lead author Vishal Patel.

“Prior studies have generally been cohort studies assembled one airline, one country, or one cancer site at a time,” Patel, a physician and health care policy researcher at Harvard, told Gizmodo. “They tend to be limited by small numbers of deaths and by the choice of comparison group—aircrew are healthier, better educated, and more affluent than the general population, so whichever comparison you pick does a lot of the work.”

This study takes a different approach, one that only became possible in recent years. In 2020, U.S. death certificates began to routinely link deceased people to their usual occupation. This change made it much easier for the researchers to compare radiation-related cancer deaths across many different jobs using just one large source of data. These cancers include lymphoma as well as breast, thyroid, and prostate cancers, to list a few.

The team also included other comparisons to check against their hypothesis, such as cancers not linked to radiation. And they singled out two professions in particular to act as a sort of positive and negative control against pilots and flight attendants: nuclear technologists, who are regularly exposed to different sources of ionizing radiation, and ground aircrew members, who only share some of the same environments as flight aircrew employees.

Overall, the team analyzed 12.7 million deaths between 2020 and 2024 across 503 occupations; this included roughly 14,000 pilots and 7,000 flight attendants.