An investigation into how much damage could be caused by the wrecks is being carried out by rescue divers from Sweden’s Coast Guard, who will be focusing on four sites in the next few weeks.
Pontus Ekström, one of the divers, says that sooner or later the vessels are bound to fall apart.
"You know that when many went under, they had fuel, diesel, fuel oil or other hazardous products on board. What we are worried about is that when they disintegrate it will come out into our sensitive marine environment,” he told news agency TT.
By looking at several key shipwrecks, he believes that Sweden’s Coastguard will improve its understanding of “how to deal with the others”.
The divers will take sediment from the sea bed around the ships as well as samples of metal from their hulls.
It is hoped that the results will help marine experts to determine when a leak might happen and how practical it would be to remove hazardous substances in advance.
“It’s fun to be involved in advance of any disaster,” said Ekström.
The announcement comes a week after Sweden's Coast Guard rescued a ship carrying 52 tonnes of oil from Stockholm's archipelago, where it was feared it might sink.