TasPorts is restricting commercial shipping at Devonport two weeks after the cement carrier Goliath allided with two berthed tugs, sinking them.

The incident caused oil spill at berth 3 West, and TasPorts said environmental protection remains the top priority as salvage operations continue.

TasPorts chief operating officer Stephen Casey said a risk assessment undertaken by TasPorts and the Tasmania Environment Protection Authority determined ships operating in the vicinity of the incident area pose environmental risks.

“[The risk assessment] has determined propulsion wash from large commercial vessels assisted by tugs operating close to the incident site poses a significant risk of destabilising the wrecks and oil spill boom and comprising the safety of people,” Mr Casey said.

“To ensure the ongoing high standard of environmental and maritime safety, TasPorts harbour master has issued an instruction restricting large commercial vessel access to Devonport 4 West berth, where towage assistance is required. Further, Devonport 5 West berth will be limited by a number of conditions, to minimise the impact of propulsion impact on the wreck site and containment area.”

Mr Casey said the restrictions would remain in place until the wrecks are recovered from the Port of Devonport.

“Whilst the expected date for completion of the recovery remains uncertain, we anticipate it will be completed prior to 5 May 2022,” he said.

“TasPorts has worked hard to minimise disruption to customers as a result of the incident. The ongoing daily sailings of TT-Line and SeaRoad support our ongoing commitment to facilitate trade, as well as the arrival of Kondili for Cement Australia earlier this week at Berth 1 West.

“We will continue to closely monitor all shipping movements in the river, until the successful recovery of the two tugs can be completed, at which point the containment booms can be removed and full shipping activity re-instated.”

Mr Casey said the ongoing risk of further pollution from the submerged tugs is being carefully managed as planning for the next phase of salvage operations progresses and the port authority continues to re-instate commercial shipping operations where it is safe to do so.

“TasPorts has worked tirelessly alongside the EPA to contain and remove a significant volume of spillage since the incident took place two weeks ago. Whilst the response has been successful, small pockets of oil remain inside the submerged tugs and as such, the site remains under active management to minimise the further release of oil, with the containment boom and its ongoing integrity remaining vital to the response,” Mr Casey said.