"We have a case of clear violation of European and international law with deadly results," he said.

"It's important ... to make sure that criminal cases like this will not go unnoticed and will not be repeated in the future."

The Probo Koala -- Dutch-chartered, Greek-managed and Panamanian-flagged -- was impounded on Wednesday by Estonian police after a criminal investigation began on suspicions it had leaked similar toxic materials into the Baltic sea.

"In simple words it is prohibited to export hazardous chemicals and wastes to non-EU countries," Dimas told a press conference at the Estonian harbour where the ship was seized.

"This defenceless country (Ivory Coast) was a victim of this criminal act," he said.

The commissioner said there was a great need for member states of the EU to better implement and apply European law on toxic dumping which had been revised and beefed up last July.

"Legally we have the means to fight illegal transportation of waste. What was needed was better policing in such transit places as harbours, he added.

The prosecutor's office on Wednesday impounded the vessel in the Estonian port of Paldiski. The Baltic state had been asked by Ivory Coast to detain the ship, after an eighth person in the West African country died from exposure to the waste.

Thousands of people in Ivory Coast have suffered vomiting, stomach pains and other symptoms caused by toxic fumes from waste from the ship in late August. The incident has stretched the country's health services and forced its cabinet to resign.

Estonia's Environment Ministry said tests of the Baltic waters around the vessel showed similar substances as those in the Ivory Coast.

But Trafigura, the Dutch-based oil trading firm which chartered the ship, denied the vessel had been impounded and in a statement said the waste on the Probo Koala in Estonia was not the same waste as discharged in Abidjan.

The firm described the waste dumped in Ivory Coast as "chemical slops", a mixture of gasoline, spent caustic soda and water and said it was a normal by-product of cleaning tanks used to transport fuel.

Environmental group Greenpeace on Thursday welcomed the decision by the Estonian government to impound the ship, and the signal by Brussels that the EU would use the Probo Koala case as an example in dealing with other illicit toxic dumping.

French embassy officials on Tuesday said toxic matter recovered from 13 sites in Ivory Coast's main city Abidjan would be shipped to France for disposal.

In the Ivory Coast, medical personnel had carried out 80,000 consultations linked to the dumping by Monday, an official said.