Thyroid cancer incidence due to technogenic exposure in childhood.

Thyroid cancer incidence was studied in the cohort of residents of Ozyorsk and Kyshtym, the nearest upwind cities to the Mayak Production Association (Mayak PA), Russia's first plutonium production facility, which has been in operation since 1948. Radioactive contamination of areas around the Mayak PA were from unmonitored releases of inert gases produced by industrial reactors and also from the release of uranium fission products from a radiochemical plant stack where irradiated uranium blocks were refined. Iodine-131 (131I) was the main contributor to the technogenic dose from atmospheric releases.