Radiation-induced chromosome aberrations in nuclear-dockyard workers.

The incidence of chromosome aberrations in peripheral blood lymphocytes of 197 dockyard workers has been followed over a 10-yr period. These workers were exposed to mixed neutron-gamma radiation during the refuelling of nuclear reactors, but most exposures were below the internationally accepted maximum permissible level of 5 rem per yr. There was a significant increase in chromosome damage with increasing exposure; aberration frequency was a linear function of dose and was unfluenced by age and time of blood sampling after exposure.