The two-day seminar was also attended by experts, including authors of a study of environmental impact of the project and members of the commission in charge of evaluation of the study, the Croatian environmental organisation "EKO Kvarner" said in a statement on Sunday.
The meeting was closed to public because the environmental impact study was classified as a military secret considering the importance of oil pipeline facilities and the wish of some experts to remain anonymous.
The participants found that the study was flawed and that the proposed solution to the problem of ballast water was not always reliable or applicable. They also claimed that the cathodic protection of the pipeline was poorly executed and this might cause external corrosion.
The section of the study dealing with the cost-effectiveness of the project has erroneous data, including financial indicators of the importance of tourism to the economy of the Kvarner region and Croatia as a whole, the statement said.
Participants from other countries said they would inform the public and government officials in their own countries about the findings of the seminar.
The project provides for the transport of Russian oil by pipeline via Belarus, Ukraine, Slovakia and Hungary to the Croatian oil terminal at Omisalj on the island of Krk and from there to Western destinations by tanker.