Two divers from the team involved in the salvage of the container ship Rena have had to be treated in Tauranga Hospital in separate incidents in the last month.
The container ship grounded on Astrolabe reef on 5 October 2011.
The divers from Resolve Salvage and Fire are preparing to remove the wreck's submerged accommodation block, scheduled to start in December.
One diver reported breathing problems while at a depth of 34 metres and was told to flush his helmet and return to the surface.
It was later found that a poor seal had meant small amounts of exhaled carbon dioxide had accumulated in the helmet.
The other diver's umbilical device snared twice while ascending from a depth of 46 metres and had to descend to clear the obstacles. He had difficulty while decompressing and was taken to hospital.
Neither diver suffered significant injuries.
