For more than a century, the United States relied on TNT for military weapons and commercial mining. It was plentiful and cheap, selling for just 50 cents a pound a couple decades ago.

Produced by the millions of tons for both world wars and into the 1980s, TNT filled artillery shells and bombs while making it possible to blast apart rock to build roads and make cement for home foundations and major infrastructure projects.

But making TNT, or trinitrotoluene, creates hazardous waste, and by the mid-1980s the Defense Department had shut down the last facility in the United States that made it. Foreign suppliers — primarily in China, Russia, Poland and Ukraine — stepped in, offering the explosive at low prices while dealing with the hazardous waste themselves.

A second and important source of supply for commercial use had been TNT recovered from munitions like land mines, shells and bombs that the Pentagon regularly decommissions. While the weapons were deemed too old for use by American troops, the explosives inside of them were typically still fully viable and could be recycled.

But according to officials in the civilian blasting industry, those sources have dried up as the U.S. military has elected to keep older weapons in its arsenal since Russia invaded Ukraine in 2022.

Poland had been the Pentagon’s sole authorized supplier of TNT. But it has been sending much of what it makes across its border to Ukraine, which is using all that it produces for its own military purposes.