A group of former deep sea divers are suing the Norwegian government for damaging their health in the early years of the North Sea oil boom.
Norwegian oil industry divers say they worked too deep below the sea
Lawyers for the 24 divers say some of them were sent to a depth of 400m. The safe limit is now set at 180m.
"The state conducted medical experiments on an entire group," lawyer Marius Reikeraas told Oslo city court.
Norway says it has already offered compensation to divers who have been totally or partially disabled.
About 200 divers were offered sums up to 2.5m kroner (US$458,000;309,000 euros) in March 2004.
But a similar case to the present one ended in August last year with the government being ordered to pay a group of other divers up to 6.5m kroner.
The "pioneer divers", as they are known, say they suffered physical and psychological damage in the 1970s and 1980s as they laid the groundwork for the Norwegian oil industry, helping to make their country one of the richest in the world.
They say the government knew or should have known the dangers when it sent them to work at extreme depths.
"This is a test case for the Norwegian government when it comes to respecting human rights," said Mr Reikeraas.
The government is appealing against the verdict in last year's case, and when that and the currently case are finally settled, observers expect a flood of new claims from former divers.