A United States congressman has raised concerns about the potential of a terrorist attack on a shipment of weapons-grade plutonium, which will pass within 200 miles of the Irish coast in two ships in the next few weeks.
Mr Ed Markey, a Democratic member of the House of Representatives, wrote to the US Secretary of Homeland security, Mr Tom Ridge questioning the adequacy of security measures in relation to the shipment of 140 kilogrammes of plutonium oxide.
The material is from the US military's bomb-making programme and is being shipped from Virginia to France, where it will be made into fuel rods for nuclear reactors.
The ships are due to arrive in Charleston, South Carolina, later this week, where the nuclear material will be loaded. The return voyage, to Cherbourg, passing anywhere between 150 and 200 miles off the coast of Cork, is expected to take up to two weeks.
The plutonium will then be trucked to Caderache, a nuclear plant in Provence. It is estimated that there is enough material to make over 60 atomic bombs.
According to Greenpeace, Ireland could object to the shipment on the basis of safety at Caderache, where two workers were contaminated during an accident last week. The European Commission has previously raised concerns about safety at the plant, according to Greenpeace.