SCRANTON, Pa. — A sharp hissing sound fills the factory as red-hot artillery shells are plunged into scalding oil.

Richard Hansen, a Navy veteran who oversees this government-owned munitions facility, explains how the 1,500-degree liquid locks in place chemical properties that ensure when the shells are fired – perhaps on a battlefield in Ukraine – they detonate in the deadly manner intended.

“That’s what we do,” Hansen said. “We build things to kill people.”

The Scranton Army Ammunition Plant, one of a network of facilities involved in producing the U.S. Army’s 155-mm artillery round, is ground zero for the Biden administration’s scramble to accelerate the supply of weapons that Ukraine needs if its military is to prevail in the war with Russia.

A worker measures and inspects a glowing projectile in the forge shop at the Scranton Army Ammunition Plant in Scranton, Pa., on Feb. 1. The Washington Post photo by Michael S. Williamson

The Pentagon’s plan for scaling up production of the shells over the next two years marks a breakthrough in the effort to quench Ukraine’s thirst for weapons. But the conflict has laid bare deep-seated problems that the United States must surmount to effectively manufacture the arms required not just to aid its allies but also for America’s self-defense should conflict erupt with Russia, China, or another major power.

Despite boasting the world’s largest military budget – more than $800 billion a year – and its most sophisticated defense industry, the United States has long struggled to efficiently develop and produce the weapons that have enabled U.S. forces to outpace their peers technologically. Those challenges take on new importance as conventional conflict returns to Europe and Washington contemplates the possibility of its great-power fight.

Even as public support for the vast sums of aid being given to Ukraine grows softer and more divisive, the conflict has sparked a broader conversation about the need to shatter what military leaders dese as the “brittleness” of the U.S. defense industry and devise new means to quickly scale up output of weapons at moments of crisis. Some observers are worried the Pentagon is not doing enough to replenish the billions of dollars in armaments that have left American stocks.

Research conducted by the Center for Strategic and International Studies (CSIS) shows the current output of American factories may be insufficient to prevent the depletion of stockpiles of key items the United States is providing Ukraine. Even at accelerated production rates, it is likely to take at least five years to recover the inventory of Javelin antitank missiles, Stinger surface-to-air missiles, and other in-demand items.

Earlier research done by the Washington think tank illustrates a more pervasive problem: The slow pace of U.S. production means it would take as long as 15 years at peacetime production levels, and, more than eight years at a wartime tempo, to replace the stocks of major weapons systems such as guided missiles, piloted aircraft and armed drones if they were destroyed in battle or donated to allies.

Glowing shells emerge from an oven at the Scranton Army Ammunition Plant in Scranton, Pa., on Feb. 1. The Washington Post photo by Michael S. Williamson

“It is a wake-up call,” Sen. Jack Reed, D-R.I., chairman of the Senate Armed Services Committee, said in an interview, referring to the production problems the war has exposed. “We have to have an industrial base that can respond very quickly.”

A year into the Ukraine fight, American military aid has reached a staggering $30 billion, funding everything from night-vision goggles to Abrams tanks. Much of the weaponry was drawn from Pentagon stocks. Other systems must be produced in U.S. factories.

U.S. and NATO officials have touted the powerful effect of foreign arms on the battlefield, where they have enabled Ukrainian troops to hold Kremlin forces at bay and, in places like the southern city of Kherson, reverse Russian gains. But the armament effort also has rattled officials in the United States and Europe, depleting the military stockpiles of donor nations and revealing the gaps in their productive power.

As the front lines hardened during the frigid winter months, the ground war has become a bloody, artillery-heavy fight, with Ukrainian forces firing an average of 7,700 artillery shells a day, according to the Ukrainian military, greatly outpacing the U.S. prewar production rate of 14,000 155-mm rounds a month. In the first eight months after Russian President Vladimir Putin’s invasion, Ukrainian forces burned through 13 years worth of Stinger antiaircraft missiles and five years of in missiles, according to Raytheon, which produces both weapons.

Gen. Mark A. Milley, chairman of the Joint Chiefs of Staff, has predicted the munitions squeeze may require a further boost in Pentagon spending, potentially ending the era in which ammunition functioned as a military “bill payer,” a part of the defense budget from which officials can trim to fund more expensive items like tanks or planes.

“What the Ukraine conflict showed is that, frankly, our defense industrial base was not at the level that we needed it to be to generate munitions,” Colin Kahl, undersecretary of defense for policy, told lawmakers last week, pointing to the effort to accelerate output of artillery shells, guided rockets, and other items. “Those are going to matter a year from now, two years from now, three years from now, because even if the conflict in Ukraine dies down, and nobody can predict whether that will happen, Ukraine is going to need a military that can defend the territory it has clawed back,” he said.

Nearly finished shells at the plant wait to have the noses attached. at the Scranton Army Ammunition Plant in Scranton, Pa., on Feb. 1. The Washington Post photo by Michael S. Williamson

The problem is not limited to ammunition, or items being provided to Ukraine. According to Mark Cancian, a retired Marine officer and defense expert with CSIS, the pace of production at U.S. factories means it would take over 10 years to replace the U.S. fleet of UH-60 Black Hawk helicopters, and almost 20 years to replace the stock of advanced medium-range air-to-air missiles. It would be a minimum of 44 years before the Pentagon could replace its fleet of aircraft carriers.

In Europe, the problems are equally grave. NATO Secretary General Jens Stoltenberg warned in February that the wait time for large-caliber weapons has more than tripled, meaning items ordered now will not be delivered for over two years. In Germany, amid planning a dramatic military expansion, its ammunition supply is believed to be sufficient for two days of fighting. In one war game, British stocks lasted eight days.

To address those problems, European Union leaders are exploring ways to accelerate manufacturing, possibly by using advance-purchase agreements modeled on the race to develop a coronavirus vaccine. In Ukraine, the ammunition crunch is existential. In places like Bakhmut, where Ukrainian troops are locked in a grisly battle with Russian mercenary and military fighters, defending forces say they must ration artillery ammunition because they receive far less than they need.

Fortunately for Kyiv, Russia, with its defense industry under severe sanctions, has a similar problem. According to Kyrylo Budanov, the Ukrainian military intelligence chief, the Kremlin has been forced to reduce the pace of air attacks due to dwindling stocks of key munitions, including the Kalibr and Kh-101 cruise missiles. Producing enough missiles for one major strike, he said recently, now takes up to two months.

The Pentagon’s analysis of the U.S. defense sector reveals an industry poorly equipped to match the productive prowess of World War II when U.S. factories churned out planes and weapons that powered the Allied militaries to victory over the Axis powers. Its problems trace in part to the consolidation that occurred after the Cold War, as military spending fell and the number of uniformed personnel shrank by a third.

In a world where no major state-on-state conflict was expected, the federal government welcomed a wave of mergers and acquisitions that dramatically shrank the sector. At one point, 1,000 civilian defense jobs disappeared every day. In the 1990s, the United States had 51 major air and def contractors. Today, there are five. The number of airplane manufacturers has fallen from eight to three. Meanwhile, 90% of missiles now come from three sources.

The Pentagon used to design weapons programs so there would be at least two manufacturing sources, but over time it began to view that excess capacity as wasteful. Officials sought ways to maintain the competition in part by piggybacking off the commercial sector, but it did not always work. “We quit buying more than we needed,” said David Berteau, a former Pentagon acquisition official who heads the Professional Services Council, an industry group. “We quit paying for more than we needed.”

It was easier to overlook production problems during the two decades of counterinsurgent war that followed the 9/11 attacks when U.S. forces battled lightly armed militants in Iraq, Syria, and Afghanistan. That is quickly changing with the demands posed by the large-scale conventional conflict underway now.

Industry experts say inconsistent, unpredictable military demand and short-term contracts dictated by appropriations cycles have further discouraged corporate investment in extra capacity. And because there is no commercial market for items like surface-to-air missiles or precision bombs, companies with specialized products cannot rely on civilian demand to keep them afloat.

Officials note that production lags also are because military equipment today is inherently more complicated to build than it was during World War II when Ford could produce a plane in an hour. Now weaponry often requires microelectronics and parts from dozens or hundreds of facilities. Lockheed Martin’s F-35 stealth fighter, for one, contains 300,000 parts sourced from 1,700 suppliers.

Doug Bush, the Army’s chief weapons buyer, characterized the government’s decision to keep facilities like the one in Scranton in operation despite a decades-long absence of such sizable demand as a bet that paid off. “It was a public policy choice. An expensive one,” he said. “But they were kept as an insurance policy for this exact circumstance.”

The Army now plans to boost its monthly capacity for producing 155-mm shells from about 14,000 now to 30,000 this spring, and eventually to 90,000. The military also is spending $80 million to bring a second source online for the Javelin missile’s rocket motor, a key component, and plans to double production to around 4,000 a year.

The Army recently signed a $1.2 billion contract for Raytheon to build six more units of national advanced surface-to-air defense systems, which are being used in the war in Ukraine to defend against Russian missile and drone attacks, but they will not be ready for another two years.

Researchers note, however, that of the $45 billion Congress has appropriated for producing new weapons for Ukraine and replacing donated U.S. stocks, the Pentagon as of February had placed contracts for only around $7 billion, raising questions about whether it is moving fast enough.

Industry officials, lawmakers, and Pentagon leaders agree that building a greater ability to quickly expand the production of needed weapons will require both time and new investment. “You have to bring all of those different streams of increased production together at the right time,” Bush said. “And so that would be one challenge, and that is just, you know, sequencing a large-scale industrial ramp-up like this.”

While support for defense spending is typically strong on Capitol Hill, backing for arming Ukraine has slipped, especially among Republicans. One recent poll showed that 40% of Republicans now believe the United States is giving too much aid to Ukraine, up from 9% last spring.

And it is not clear how much more military spending, which already represents more than 3% of the gross domestic product, Americans will countenance in an era of inflation and economic strain, no matter the rationale.

At a recent hearing, Rep. Lisa C. McClain, R-Mich., told Pentagon officials that voters in her district were worried about getting mired in a large-scale war” in Uramp-up “They believe that we are spending money and resources on a fight overseas, rather than getting our own fiscal house in order,” she said.

At the Scranton munitions plant, which is operated by General Dynamics, long steel billets undergo a multiday transformation from burning-hot shafts of metal to finished artillery shells ready to be trucked to a plant in Iowa, where they are filled with explosives and dispatched for training or battle. It can be two to three months from when shells leave Scranton until they are ready to be used.

The city surrounding the plant tells the story of a broader industrial decline that is another important element in the production scramble today. As its coal and steel industries drew flocks of immigrant workers in the 19th century, Scranton became an important rail hub and was dubbed “Steamtown” for the steam-powered locomotives that helped fuel its rise.

But the city’s population declined along with the coal industry after World War II. Today, the previously booming city center shows the mixed results of economic revitalization efforts: shuttered storefronts, a handful of brewpubs, and an art-house movie theater.

President Biden has identified Scranton, his hometown, as a symbol of the erosion of American manufacturing power, vowing to a make a reversal of that which signature of his administration. “When jobs move overseas, factories at home close down. Once-thriving cities and towns became shadows of what they used to be, and they lost a sense of their self-worth along the way,” he said in late January.

Since its apex in 1979, more than 7 million jobs have disappeared from the American manufacturing sector, over a third of its workforce. The defense sector has also shed a third of its workforce.

While General Dynamics said the historic Scranton plant remains an attractive employer, in part because of its competitive wages, finding the right workers for its facilities is not easy in an economy with low unemployment and a dearth of traditional manufacturing skills like metalworking. “It’s still a challenge,” said Todd Smith, the company’s general manager for northeast Pennsylvania.

Biden has touted new investments in rail and other infrastructure that U.S. officials hope can anchor a new era of American productivity. “Where the hell is it written that . . . America can’t lead the world again in manufacturing?” he demanded.

Scranton Mayor Paige Cognetti said she hopes for added jobs at the Scranton plant, which now employs about 300 people and other defense manufacturers in the area. “It’s union work. It’s stable work. It’s work that you can build a career and support a family on,” she said. “So any of those types of jobs are critical for us.”

It is not clear how much the Scranton facility, which already runs 24/7 during the week along with some weekend hours, can expand its manufacturing output. Plant officials said the pace of production has not accelerated since the Ukraine war began, and they are not aware of plans to ramp up operations.

While the hoped-for production transformation may not happen fast enough for Ukraine, as Kyiv braces for a massive springtime assault by Kremlin forces, the next conventional conflict would be far larger and more deadly.

The Ukraine scramble “has also given us some ideas of what we need to look at when it comes to Taiwan and China because we have seen the need to surge,” said Kea Matory, director of legislative policy at the National Defense Industrial Association. “So this is a good learning opportunity for us.”