The harbor is Europe’s largest refinery center and a trading hub for refined products such as gasoline and diesel. Some ships have been diverted or are waiting outside the port until space is available, said Jeroen Kortsmit, manager for commercial affairs at Royal Dirkzwager.

“A lot of tanks are fully loaded,” Kortsmit said by phone from Rotterdam April 27. He joined the company, which provides shipping information to terminal operators around the port, 24 years ago and said he has never seen storage this full before.

The Organization of Petroleum Exporting Countries, accounting for about 40 percent of global supply, agreed to cut output three times since September as demand crumbled. Oil prices have plunged 66 percent from a record $147.27 a barrel reached in July.

Rotterdam can store 11.9 million cubic meters of crude, port data from 2007 show. That’s equal to about 75 million barrels or enough to supply the 27-nation European Union for about five days.

Some on-shore storage tanks for oil products are either full or have no unreserved space available, Pieter Kulsen, a Rotterdam-based refined oils consultant at PJK International BV, said by phone yesterday.

The port doesn’t monitor how much capacity is left in on- shore tanks, Sjaak Poppe, a spokesman for the Port of Rotterdam, said by phone on April 27.

Companies with oil-storage facilities at Rotterdam include The Hague-based Royal Dutch Shell Plc, Europe’s biggest oil company, London-based BP Plc, the second-largest, and Rotterdam- based Royal Vopak NV, the world’s largest oil and chemical storage company. Company officials declined to comment.