One person was killed and about a dozen injured when Russian aircraft carrier Admiral Kuznetsov caught fire at a Murmansk shipyard renovating the warship, international media outlets have reported.

A source told the Russian government-owned TASS news agency that one body was found at the site of the fire, 12 people were being treated for injuries, and two more people remained unaccounted for. Those that were being treated for injuries were mostly suffering from inhaling toxic fumes from the fire, including burning diesel fuel.

The fire may have started due to violations of safety protocol while workers conducted welding on the ship, TASS reported. Russian government-owned outlet Sputnik cited the head of the United Shipbuilding Corporation (USC), Alexei Rakhmanov, as saying the fire broke out during welding work near the first energy compartment, when a spark fell into a hold space where fuel was handled.

Zvyozdochka Ship-Repairing Center, part of the United Shipbuilding Corporation, has been refurbishing the aircraft carrier since 2017.

TASS reported the fire grew to consume 120 square meters of space on the ship and was being put out with firefighting foam. NBC reported that “fire control teams were struggling to contain and extinguish the blaze, while dramatic videos of the ship surrounded by thick plumes of smoke have proliferated on social media.”

Russia’s Northern Fleet told TASS that two firefighters were injured and have been treated. The military officials also said there were no arms or munitions on the ship at the time of the fire.

About 400 military and civilian personnel were on the ship when the fire broke out and were evacuated.

In 2017 Russia had planned to put its only aircraft carrier into a major three-year maintenance availability to upgrade its launch and recovery systems, but instead the carrier was sent to the Eastern Mediterranean in late 2016 to participate in strikes in support of Syrian dictator Bashar al-Assad. In November 2016, a fighter participating in those operations crashed while trying to land onboard the carrier. A month later, a second fighter crashed while trying to land. Both crashes were attributed to faulty arresting gear on Admiral Kuznetsov. The carrier was pulled from the Mediterranean the following month.

Since that deployment, the carrier has been in the yard at Murmansk, a northern port city on the Barents Sea. In October 2018, the carrier was sitting in one of the world’s largest floating dry docks when the dry dock sank and the carrier was damaged, international media reported. Admiral Kuznetsov was undergoing repairs from that incident as well as its originally planned repairs and upgrades when today’s fire broke out. The Barents Observer previously reported that these repairs and upgrades were to set to last until 2021, and it’s unclear what today’s fire will mean for that timeline.

Though Russia’s sole carrier has experienced a number of mishaps in recent years, the fire due to a welding mishap is not unique to Russia.

U.S. Navy destroyer USS Oscar Austin (DDG-79) was badly damaged in a November 2018 electrical fire “caused by BAE hot-work,” according to a Navy fire investigation, referencing the BAE Systems ship repair crew overseeing the destroyer’s modernization effort at the time of the fire. The damage was so severe that the ship is not expected to rejoin the fleet until 2022.

In May 2019, the commanding officer of USS Fitzgerald (DDG-62), which was being repaired at Ingalls Shipbuilding in Mississippi following its 2017 fatal collision, wrote that a series of 15 fire safety incidents put the ship and its crew at risk.

“The lack of fire safety is a major concern on this project and I am extremely concerned we are on a path to have a catastrophic fire event on board. NSA (Naval Supervisory Authority) and KTR (contractor) leadership have taken measures to curtail, but they have been marginally effective. I have seen improvements in government [oversight] in the past few months, but little change in craft deck plate compliance. The most recent incident is uncomfortably similar to the recent USS Oscar Austin industrial fire,” Cmdr. Garrett Miller wrote in a May status report submitted to Navy officials and obtained by USNI News.

Most recently, last month amphibious assault ship USS Iwo Jima (LHD-7) caught fire during its maintenance availability in Mayport, Fla. As of Thursday, Navy officials have declined to give USNI News an update on the cause of the fire or elaborate on the damage it suffered.