The Port of Rotterdam Authority detected no radiation above prescribed standards on five vessels that left Japan after March 14 and which were inspected in the last five days, the Journal of Commerce reports.
The four container ships and one car ship were inspected before they entered port with remote sensing instruments to measure the relevant radiation, focusing on those parts of the ship that are exposed to touch during transshipment.
"The lashing rods and the top part of the containers were examined particularly closely,' the port authority said in a statement. "The radiation in itself is not the main concern here; it is the fact that the radioactive parts can cause contamination when absorbed into the body via the skin or mouth."
The port authority said it will continue to inspect all ships from Japan until May 1, when it will decide whether more inspections are needed.
It said it may make exceptions to the screening for ships that have been screened in a different port for radioactivity and received a certificate stating so.