The oil contamination from a cargo ship that grounded on a New Zealand reef almost two months no longer poses a health risk in the consumption of shellfish, crabs and seaweed, health authorities said Friday. The Bay of Plenty regional health authority said it had been conducting a shellfish monitoring program after the Liberian- flagged Rena ran on to the Astrolabe Reef, off the east of the North Island, on Oct. 5. An estimated 360 tonnes of the vessel\'s 1,700 tonnes of heavy fuel oil spilled into the sea. A health warning advising against the collection and consumption of shoreline seafood was no longer necessary and had been lifted, said a statement from the authority. Although some samples of shellfish from the most affected shoreline showed traces of hydrocarbon from the oil spill, it had been \"well below acceptable food safety levels.\" \"The amount detected has also fallen during the period since the last significant oiling events,\" said the statement. The announcement came as the mayor of the port city of Tauranga, the Rena\'s destination before it grounded, called for the release of investigators\' findings into the cause of the accident as soon as possible. Mayor Stuart Crosby told Radio New Zealand he believed investigators already knew what happened. He said vessels had voyage data recorders, like an aircraft\'s black box, and the Rena\'s was removed for analysis within the first few days. \"So I\'d suggest they\'ve got a pretty good idea already what\'s happened and I think they need to explain that to our community as soon as possible, in the context that they\'re still doing some more work,\" said Crosby. The Transport Accident Investigation Commission told Radio New Zealand that information was successfully downloaded from the recorder, but no date for the release of a promised interim report had been set. By Thursday, salvors had removed 166 of the vessel\'s remaining 1,280 cargo containers before bad weather stopped the operation, according to Maritime New Zealand. A total of 962 tonnes of solid waste has been collected by oil spill response clean-up teams, it said. Wildlife experts began releasing oiled birds back to the wild after treatment late last month. Two senior officers of the boat\'s Filipino crew have been charged in connection with the grounding and the pollution.