Radioactivity levels in locally-caught seafood are too low to be considered a health concern, the Isle of Man government laboratory has said.
Scientists carry out annual checks on the impact of radioactive discharges from Sellafield into the Irish Sea.
Their 2009 report found that background radiation levels were "consistently low" in harbour basins and beaches.
Despite Sellafield discharges remaining at a historic low, the government said it remained opposed to the plant.
The report, released by the Department of Environment, Food and Agriculture, said the impact of the nuclear plant on the Irish Sea was in decline.
It concluded that even people who ate large amounts of local seafood were unlikely to receive more than 2% of the acceptable annual limit for radiation exposure.
Environment Minister John Shimmin said: "Whilst I accept the fact that there is no present day health risk from Sellafield, it is quite obvious from the monitoring that discharges from across the water have the very real ability to contaminate our environment here on the Isle of Man.
"I am acutely aware that releases of radioactive material from Sellafield have the potential to have a detrimental effect on our fishing industry and economy, or even directly upon human health.
"I stress that we are in no way content with the present situation which permits radioactive waste to go into the Irish Sea.
"The UK Government has given a commitment to cut Sellafield's discharges to near zero by the year 2020. I believe Sellafield should do everything possible to achieve that objective."