Seven sailors are missing after two chemical tankers caught fire overnight off Romania's Black Sea coast, hit by drones near the mouth of the Sulina canal — the anchorage that guards the Danube, the shipping route Ukraine now depends on most.

Romania's naval authority received the emergency alert from the Wine Trader, a San Marino-flagged tanker struck 13 nautical miles southeast of the Sulina canal, one mile outside Romanian waters. Five of its 12 crew were rescued. Seven remain unaccounted for. The ship was empty of cargo, like its companion vessel, but that offers little comfort to anyone anchoring there this week.

The second ship, the Comoros-flagged chemical and oil tanker Yara J, caught fire late Wednesday 8-10 miles southeast of Sulina — inside Romanian national waters. All of her crew are safe. Romanian authorities said initially it was not clear whether she had been attacked.

What does this change for Black Sea shipping?

The mechanism is simple and grim. Russia has spent months bombing Ukraine's own Black Sea ports, which pushed Kyiv's export traffic onto Danube river ports and coastal routes hugging Romania and Bulgaria. That shifted the risk from Ukrainian waters to NATO's doorstep. Now the strikes have arrived there too.

President Nicusor Dan confirmed the two ships were hit by drones, though he declined to attribute them. "Two air drones hit them," Dan told reporters in Brussels ahead of an EU leaders' summit, adding that only a few hours had passed and Romania was still gathering information. "There will be a reaction from the Romanian state," he said.

The rescue effort itself is stalled by weather. Romania's interior ministry sent two Black Hawk helicopters and two ships with medical crews. "At the moment, the rescue cannot be done safely because of very big waves," the ministry said in a statement.

A pattern, not an outlier

This is not an isolated strike. NATO said two further vessels were targeted overnight: the Marshall Islands-flagged bulk carrier Sea Destiny, inside Romanian waters, and the Tanzanian-flagged tanker Dania J, moored in the Ukrainian Danube port of Izmail. NATO's statement mentioned no casualties.

Over the past 10 days, drones have hit at least five other cargo ships near the coasts of Romania and Bulgaria, both NATO members. Those strikes, all just outside NATO territorial waters, killed at least 23 sailors.

The location matters as much as the count. Both Wine Trader and Yara J burned where ships queue to enter the Sulina canal, waiting out weather delays and congestion. That anchorage is the queue for the Danube. Hit the queue and you hit the throughput of Ukraine's fallback export corridor — and Romania's own grain trade, since Romania is also a major grain exporter alongside Russia and Ukraine.

The policy response is forming, slowly

Bulgarian Prime Minister Rumen Radev said EU leaders would discuss a proposed moratorium on attacks on civilian ships in the Black Sea. NATO Secretary General Mark Rutte, after meeting Dan and Radev on Thursday, said: "NATO will continue to work closely with our Allies in the Black Sea, adjusting our deterrence and defense posture as needed."

Romania's Foreign Minister Oana Toiu put the stakes bluntly at a security conference in Warsaw earlier this week. "We're looking at the Black Sea as a global food artery," she said. "It is currently, unfortunately, the deadliest sea when it comes to the number of casualties of sailors in the last months. That means we need to increase our investments in deterrence, defense."

Context for the escalation: Romania shares a 614-km border with Ukraine, much of it along the Danube, and has reported repeated Russian drone breaches of its airspace over the past four years. Ukraine, for its part, has targeted Russian ships near the mouth of the Don River in the Azov Sea.

For carriers, forwarders and grain traders, the practical question is whether insurance and crew willingness hold at Sulina if strikes continue inside or near NATO waters. A moratorium is only a proposal so far; until deterrence or diplomacy changes the trajectory, the Danube gateway stays the world's most dangerous queue.