WASHINGTON, Aug. 18 -- Before she boards her fifth flight of the week, the flight attendant completes a safety briefing, checks the exits, and confirms the galley is stocked. What she cannot check is her accumulated radiation dose. The United States does not require airlines to monitor it.

A study published Monday in JAMA Internal Medicine suggests that oversight gap is more consequential than regulators have acknowledged. Analyzing more than 12.7 million death certificates filed between 2020 and 2024, spanning 503 occupations, researchers at Harvard Medical School found that flight attendants had the highest proportional rate of radiation-related cancer deaths of any profession in the United States. Pilots ranked second. Both groups out...