In the United States, most factories that manufacture 155mm ammunition are owned by the US Army but operated by private contractors. Investment decisions lie with the Pentagon and Congress.

Bruce Jette, the Army official who dispatched Amadee to survey America’s munitions apparatus, said he pushed hard from inside the system to tackle an obvious problem. In September 2020, Jette went public, warning US lawmakers at a public hearing that upgrading ammunition factories might be expensive, but that “there is greater risk in not doing so.” Jette served as the assistant secretary of the US Army for acquisition, logistics and technology from 2018 to January 2021.

Representative Donald Norcross, a New Jersey Democrat who then chaired the House Subcommittee on Tactical Air and Land Forces, echoed Jette’s concerns, especially about plant safety. At the hearing, he noted the age of the facilities. “Why are fundamentally essential functions of defence manufacturing done in museum-like conditions?” he asked.

In a statement to Reuters, Norcross said he began tighter oversight of Army plants in 2019, and he noted that Congress increased by 15 per cent the Pentagon’s budget request for munitions facilities to $684 million in fiscal year 2021.

“Make no mistake, there was still much to be done heading into 2022,” Norcross said, “but the challenge of ammunition facilities improvement had numerous champions.”

Money wasn’t the only problem suppressing the West’s ability to prepare for war. In the decade before Russia’s 2022 invasion of Ukraine, the US military made a key decision about the kind of explosive to use for the 155mm shell and which suppliers to rely on. The choice proved unwise: It not only slowed the production rate but also has left the West struggling to quickly find enough high explosive to ramp up output.

That decision involved moving away from using trinitrotoluene, better known as TNT. The explosive is valued for its high stability, according to Thomas Klapotke, a professor of energetics at the University of Munich. That is, it can be melted and poured into shell casings without exploding.

Since before World War II, TNT has been mixed with other less-stable “explosive fillers” more familiar to chemists than to laymen – principally more-powerful octogen, called HMX or hexogen, called RDX. The standard mix used in artillery shells has hardly changed since then, Klapotke said. But with the war in Ukraine, each of these explosives is in short supply.

In a forest in western Poland, a complex on the same site where a factory was built by Nazi German occupiers to support an invasion of the Soviet Union now makes thousands of tonnes of TNT every year. The problem for Ukraine is that the factory, located near the city of Bydgoszcz, is the last surviving TNT plant in Europe or North America.

Workers there now work around the clock. It’s run by a state-owned company, Nitro-Chem, and makes about 10,000 tonnes of TNT per year. The company declined to say exactly how much. A single 155mm round typically requires about 10 kilogrammes of TNT. That means that the 10,000 tonnes of TNT would be enough to provide for about 1 million rounds, if every bit were used for 155mm shells.

Much of the TNT made in Poland is shipped to the US, according to staff at the plant. It is then packed into shells with other ingredients and added to the shrinking US Army stockpile. The oldest shells are shipped back to Poland and then on to Ukraine.

Few countries today produce TNT, primarily because of environmental concerns about contamination from the highly toxic chemicals produced in the manufacturing process.

Germany closed its last TNT plant, Schönebeck on the Elbe, in 1990. And in Britain, a TNT plant at Bridgewater in Somerset was closed in 2008, the last of at least four TNT factories in the country dating to World War II.

When the Somerset plant was slated for closure, a report by trade unions warned that Britain would lose “all national capability for the production of military explosives.” The report cited the dangers of relying on other suppliers, even allies. After all, the report noted, during the first Gulf War in 1991, Britain had been denied supplies of 155mm ammunition by one of its close allies, Belgium, where the UK had outsourced its shell production to save money.

Besides the plant in Poland, production of TNT is now concentrated in China and India. Customs records examined show at least 1,200 tonnes of TNT were exported from India in 2023 and 2024 to arms makers that supply Western forces. India also shipped large volumes of the explosive fillers RDX and HMX to Poland’s Nitro-Chem.

But both India and China also have tried to maintain good relations with Russia. And neither likely would be able to fill NATO’s needs, even if willing. “You cannot imagine just how overheated the market is at the moment,” said a European defence industry executive. “The worst thing at the moment is the global shortage of TNT and RDX. The shortage of these raw materials is the basic reason why production cannot be ramped up much more at this point.”

One factor behind America’s TNT shortage dates back to the presidency of Ronald Reagan. No facility in the US has made TNT since 1986. The Army relied on imports instead.

Decades later, in 2014, the Army began trying to transition away from TNT to a different explosive compound called IMX-101. At the time, the Army said IMX-101 was more environmentally friendly and less vulnerable to detonation by accident or terrorist attack.

But Reuters learned that last summer, about 17 months into the war in Ukraine, the Army quietly switched back to TNT for cost and efficiency reasons. IMX, while less toxic, also proved to have some environmental downsides of its own.

In a statement to Reuters, the Army confirmed for the first time publicly that “the plan changed” and it stopped producing IMX-101 for the 155mm shell last July.

“Unexpected world events and the cost of IMX led the Army to abandon IMX-101 and use TNT, which is cheaper.” The years-long use of IMX slowed the production rate such that artillery output is now 25% “higher with TNT than with IMX,” the Army said.

Even before the war, the IMX endeavour was struggling, it was found. After building the $147 million Tennessee plant to handle waste for the programme, the Army hasn’t used the facility. The reason: Rather than manufacture precursor IMX chemicals domestically, as planned, the Army imported the chemicals, negating the need for the waste plant, according to contracting records and current and former officials.

Doug Bush, the assistant secretary of the US Army for acquisitions, logistics and technology said the unused IMX facility is an “insurance policy,” adding, “We’re going to use it at some point.”

As a result of all these decisions, the Army largely came to depend on the plant in Poland for its TNT supply. And the Army’s contingency plans included relying on another facility: a TNT factory in eastern Ukraine.

In 2021, the US began importing TNT from that plant, in Rubizhne in Luhansk province, as part of a long-term $188 million deal. A person familiar with the matter said the US imported about 500 tonnes of TNT before the war started. In 2022, however, the facility was quickly captured by the Russians. Ukrainian forces destroyed it before retreating.

The US has announced plans to build its own $650 million TNT factory. It will take at least two years to complete.

In late May, inside a Ukrainian bunker not far from the front, tensions ran high among brigade commanders. Russia was on the offensive. A bank of screens showed drone-surveillance video of a stretch of frontline north of Ukraine’s second city, Kharkiv.

On May 10, Russia had launched a surprise attack, smashing through flimsy border defences to take more than 700 square kilometres in the nine days after. The brigade was holding the line along a 20-kilometer sector north of the town of Lyptsi.

Sitting to one side, the commander for artillery watched another feed – radar showing the loopy path of two Russian Orlan drones. The drones were monitoring Ukrainian positions and calling in salvos of deadly Russian artillery fire.

Colonel Ihor Obolenskyy, who’s in charge of  the brigade, said the “duel of artillery between the enemy and us” was constant. After new supplies were rushed to the front to help repel the advance, Obolenskyy said he had, at the moment, sufficient 155mm rounds.

“Why are fundamentally essential functions of defence manufacturing done in museum-like conditions?”

Representative Donald Norcross, a New Jersey Democrat and former chair of the US House Subcommittee on Tactical Air and Land Forces

But there was a different problem. Firing an artillery shell requires gunpowder, the propellant that is loaded separately and launches the shell when detonated. And to hit enemy positions, the Ukrainian guns need to fire their 155mm cannons at full range – about 25 kilometres.

The gunpowder, supplied in what he called “big tubes,” was in short supply. “We have a lot of projectiles but not a lot of big tubes,” he said. That meant the range of his guns was restricted.

The shortage of gunpowder presents yet another dire issue for Ukrainian forces – and for the West. It is made from nitrocellulose, a compound created by treating natural cellulose fibres such as cotton with nitric acid. The process is difficult and dangerous.

As with the TNT plants, Western countries have spent the years since the end of the Cold War closing powder plants. The last in the United Kingdom were shuttered in 1998, and plants closed in Romania in 2004 and in Bergerac, France, in 2007, all due to insufficient orders. Germany’s Rheinmetall has retained powder production in Aschau, Bavaria and in Wimmis, Switzerland, but those plants are unable to meet current demands.

The US Army’s sole nitrocellulose plant is located in rural Virginia. It opened in 1941 and though it is still operating, recent Army budget documents say the plant has “exceeded its useful life” and breakdowns are routine. A recent equipment failure there caused one production line to close for six weeks, said a person familiar with the matter. “The place is very fragile,” he said of the plant.

In 2012, the Army signed a deal to replace it with a modern plant that would be far more efficient, safe, and environmentally sound. The new facility would also reduce reliance on foreign suppliers. It was to open around 2015 and cost about $245 million.

The nitrocellulose project, however, is a decade behind schedule, and costs have soared to $399 million. Internal Army records and federal court records blame delays and cost overruns on contractor and subcontractor incompetence. Subcontractor Fluor Federal Solutions paid $14.5 million to settle US Securities and Exchange Commission charges related to the project. Fluor and contractor BAE Systems OSI have declined to comment, citing ongoing litigation over the matter.

The Army said the new nitrocellulose factory is “in the final stages of commissioning and qualification.” But it is not yet producing large quantities of nitrocellulose for military use. The “prove out” process – getting the chemical mix just right – could take years, people briefed on the matter said. The Army said it hopes to have the process honed by December. It said the delay has had “no impact” on the Ukrainian war effort because the legacy plant still functions.

Russia, meanwhile, has been expanding several gunpowder plants, all that date back to at least World War II. Its plant at the city of Kazan once made gunpowder for Catherine the Great. Even after demand fell following the collapse of the USSR, Russia managed to keep open its plants there and in Perm and Tambov, in part by diversifying into the supply of liquid nitrocellulose for civilian use as paints or lacquer.

In an interview with Reuters, Lieutenant-Admiral Rob Bauer, chairman of the NATO military committee, said Russia had shown it could rapidly adopt a war economy and “order their industry to give priority to the war in Ukraine.” The challenge facing Western democracies, he said, is to show they too can marshal their huge industrial resources.

In Europe, an effort to increase the 155mm supply is beginning to pay off. Total shell production there now surpasses US output, and according to a NATO official, the alliance is on track to make 2 million shells this year. “We are making progress but we are not complacent about the scale of the challenge,” the official said.

In the US, the Army took reporters on a tour in April of the recently updated shell plant in Scranton, Pennsylvania. There, officials showed off new modern lathe machine tools from South Korea. Some were still in shrink wrap.

And in May, the secretary of the Army showcased the grand opening of a state-of-the-art facility near Dallas, which will rely heavily on robots to make 155mm shells.

Still, those new machines aren’t expected to begin producing war-ready shells until the fall. Although total US monthly shell production might jump from 36,000 to 60,000 by year’s end, officials say it isn’t expected to reach the goal of 100,000 for another 18 months.

Back on the frontline, Ukraine’s soldiers hope the efforts work – fast.

One lieutenant who commanded a gun in the southern Donetsk region told Reuters that for months, he had fired so infrequently that the Russians didn’t even bother to shell his position. New supplies have arrived, he said, but he feared they were too late and too little to stop the Russians.

“What we have is still a pittance,” Oleksander said. “We are retreating village by village until we reach our homes.”

• A Reuters report