China has thrown a wrench into the global supply chain by slapping new export controls on antimony metals, ores, and oxides, effective September 15. This move could spell trouble for American arms manufacturers who are heavily dependent on this crucial resource. Companies aiming to export these materials will now need to navigate a complex licensing process for dual-use products—a requirement that might not be as benign as it sounds.

The Chinese Commerce Ministry insists that these new restrictions aren’t targeted at any specific country but are meant to safeguard China’s national security and uphold its non-proliferation commitments. However, with China producing nearly half of the world's antimony ore in 2023, and the US being a significant importer, it’s clear who could be hardest hit by this decision.

Antimony, though not widely known outside of industrial circles, is a mineral of critical importance. The US International Trade Commission classifies it as essential to bo...