'This is an important step towards establishing the principle of extended producers ''responsibility, '' said Tom Erik Okland of Friends of the Earth Norway, which has advocated the principle for several years.

About half of the PCBs in Oslo harbour have been traced back to German chemical giant Bayer AG. The rest originates from two other producers, Solutia (a division of the multinational Monsanto) and a Japanese company, Kaneka Corporation.

In a letter to Bayer AG, the City of Oslo has asked for compensation of ?3.5m to cover part of the clean-up of heavily contaminated sediments in Oslo harbour. Similar claims have been addressed to the two other companies.

BayerAG has responded to the City of Oslo that they will look into the claim. Kaneka has denied any responsibility.

Solutia has not yet responded.

Large areas of the Norwegian coast are heavily contaminated with PCBs, a fact well documented by the Norwegian Pollution Control Authorities.

Said Okland: "A Norwegian lawsuit will be considered if the PCB producers do not voluntarily participate in the cost-sharing scheme.

Our investigation has firmly established that the main sources of PCBs in Oslo harbour have been ship painting and sandblasting at shipyards. The named PCB producers supplied PCBs for ship paint, but failed to inform the shipyards about the environmental hazards involved. Such information could have prevented most of the PCB pollution along the coast."