The Karin, a 400-foot-long (120-meter-long) cargo ship, sat moored this week on Ireland’s boggy River Shannon estuary. Soon it set sail for Russia laden with a white powder that can be forged into weapons vital to Moscow’s war on Ukraine.

Alumina, the key ingredient in aluminum, goes into everything from toothpaste and lipstick to missiles and drones. A Russian-owned plant in southern Ireland is Europe’s biggest alumina refinery and regularly sends shiploads of the substance directly to St. Petersburg and other Russian ports.

Almost five years into Moscow’s full-scale invasion of Ukraine, alumina has escaped European sanctions intended to hobble Russia’s economy. That leaves the refinery in Aughinish free to send its product to Russia, where some ends up in weapons, experts say.