Cargo on a Grimaldi Group-operated ro-ro vessel off New Jersey has been fully removed a month after a fire erupted on the ship as a multiagency investigation into the blaze continues.

A fire broke out on an upper level of Grimaldi Deep Sea’s 3,950-lane-metre Grande Costa d’Avorio (built 2011) on 5 July while stevedores finished loading 1,200 vehicles and 157 containers onto the ship, which was berthed in Port Newark.

“To date, all vehicles have been removed from the cargo decks of the ship, as well as all 134 freestanding containers that were located beyond the area affected by the fire,” the US Coast Guard said on Tuesday.

“At this stage, the vessel remains in a stable condition and no fuel oil or hazardous material has released into the marine environment.”

The cars and boxes have been placed somewhere in the port facility as federal and state agencies carry out a full investigation, the Coast Guard said.

Entities looking into the fire’s cause include the National Transportation Safety Board, the Bureau of Alcohol, Tobacco, Firearms and Explosives, the New Jersey State Fire Marshal, the New Jersey State Police, the Newark Fire Arson Division and the Essex County Prosecutor.

“A comprehensive formal investigation is underway to determine the root causes and contributing factors,” the Coast Guard said.

“Due to the investigation, access to the area is now restricted, including to media.”

The Coast Guard said it will provide regular updates on the salvage operation, investigation findings and actions taken to ensure the safety and security of port operations.

“Our partnerships played a crucial role in the swift response to the initial fire, and we continue to work jointly during this phase of recovery operations to accomplish significant milestones toward the completion of salvage operations,” said Capt. Zeita Merchant, federal on-scene coordinator and captain of the Port of New York and New Jersey.

“All stakeholders involved are laser-focused on ensuring the safety of the public and response personnel, mitigating environmental impacts and minimising any impacts to the marine transportation system.”