The station should have set a better example, says Greenpeace, one of the world's leading and most controversial campaigners on conservation issues.

Its criticism came as a former Bio Station director came to its defence over the dumping controversy.

The Bio Station has admitted dumping waste from experiments into the ocean off Bermuda. It says dumping stopped more than a year ago and radiation levels were far too low to harm humans or sea life.

The policy was approved by Government and was in line with "accepted practice'' at the time, the station says.

But Greenpeace, known for its high-profile actions against pollution, condemned the station.

"Repeatedly we find that for institutions that do scientific or technical work, they are most credible when they lead by example,'' said Mr. Clifton Curtis, oceans advisor at Greenpeace International in Washington DC.

"Even if the amounts fall below the threshold of prohibited dumping from a technical perspective, it really behoves an institution like the Biological Station to go beyond the established criteria and take that extra ounce of care from a public perception perspective -- as much or more than from a risk perspective.

"This is a way of sending a message on their attitude in dealing with environmental risks to the ocean.'' But former Bio Station director Dr. Wolfgang Sterrer said the dumping was "perfectly above board''.

"I was director at the time,'' said Dr. Sterrer, now Nautural History Museum Curator at the Aquarium.

"It was agreed with the appropriate Government agencies in Bermuda that this was the best way of taking care of these low-level radioactive wastes,'' he said.

"It was perfectly above board. It was known and published. There was neither any danger to the environment nor any attempt to deceive.

"Wastes need to be disposed of in some way. Every way is controversial.

"We can only take the steps that at the time are agreed by all those people with the insight and the knowledge that they are the best ways.

"Maybe five or 10 years later you find that maybe there are better or more up-to-date ways.'' The Bio Station says it is now stockpiling its waste in the hope of arranging disposal in the US at "great expense''.

It says that as standards change on the handling of radioactive waste, it will always make its practices more stringent than required.

When Government comes up with a policy on hazardous waste it will comply "to the letter'', it says.