Mortality among Fukushima nuclear emergency workers, 2012-2021

03/07/2026

AI Summary

Overall mortality was lower than expected compared with the general male population (SMR 0.86, 95% CI 0.80 to 0.93), reflecting a healthy-worker effect.
SMRs for all solid cancers and radiation-associated solid cancers and leukaemia increased over time: below 1.0 (2012-2014), near 1.0 (2015-2017), above 1.0 (2018-2021).
No elevated suicide SMR observed; continued health monitoring recommended given marginal excess cancer mortality in later follow-up.

Occup Environ Med. 2026 Jul 2:oemed-2026-110939. doi: 10.1136/oemed-2026-110939. Online ahead of print.

ABSTRACT

OBJECTIVES: The 2011 Fukushima Daiichi Nuclear Power Plant accident involved approximately 20 000 emergency workers. Given the scale and nature of the accident, concerns have been raised regarding the long-term health of the emergency workers. This study presents the first 10 year overview of mortality among these workers.

METHODS: We analysed the mortality data for 19 358 male emergency workers (mean age in 2012: 45.5 years; SD: 11.3) from 2012 to 2021. Mortality data were monitored through linkage to national vital statistics, including the dates and causes of death. Standardised mortality ratios (SMRs) with 95% confidence intervals (CIs) were calculated using the general male population in Japan as a reference, standardised by calendar year and attained age (5 year age groups).

RESULTS: During 190 700 person-years of follow-up, 708 deaths were identified. The overall SMR was 0.86 (95% CI 0.80 to 0.93). SMRs for all solid cancers and radiation-associated solid cancers and leukaemia were below 1.0 during 2012-2014, approached 1.0 during 2015-2017 and exceeded 1.0 during 2018-2021, suggesting marginal excess mortality (both P values for trend <0.05). In contrast, the increasing trends were less evident for neoplasms excluding radiation-associated solid cancers and leukaemia. No elevated SMR for suicide was observed.

CONCLUSIONS: The overall mortality among Fukushima emergency workers was lower than expected based on general population rates, likely reflecting the healthy-worker effect. However, marginal elevations in SMRs for all solid cancers and for radiation-associated solid cancers and leukaemia emerged during later follow-up, highlighting the importance of continued health monitoring in this population.

PMID:42392612 | DOI:10.1136/oemed-2026-110939

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