If you can reach him, Gus Nasrallah, president and CEO of manufacturing equipment supplier Sharpertek in Pontiac, Michigan, can sell you a machine that cranks out the N95 face masks desperately needed by health workers treating Covid-19 patients. It will cost you $250,000 or more—but don’t expect it soon. “We’re telling them six-month delivery.”

Keith Hayward, managing director of specialty fabric maker Monadnock Nonwovens in Mount Pocono, Pennsylvania, is also deluged with phone calls. Among other products, his company makes meltblown fabric that provides the ultrafine filtration in N95 masks. He estimates Monadnock has been getting upwards of 200 calls a day. “Demand is unprecedented,” he says.

Nasrallah and Hayward are in the middle of a logjam in America’s manufacturing capacity caused by the coronavirus pandemic. The crisis has exposed the fragility created by decades of companies shrinking production on US soil and growing complex overseas supply chains, most notably in China.

China’s vast, cheap labor pool and canny government incentives have fostered an extensive ecosystem of manufacturers, suppliers, and workers that is the default place to make everything from disposable face masks to $1,000 smartphones. American consumers have benefited as essentials such as kitchenware and more complex goods like TVs and computers have gotten cheaper. Covid-19 has created a natural experiment in how well the US can manage when demand spikes and China’s rich overseas supply chains are choked or cut off.

In February, when the novel coronavirus felt like a faraway problem to most Americans, Apple warned investors that its revenues would take a hit because iPhone production was hampered by factory shutdowns in China. The same month, Fiat Chrysler halted some production in Europe because Chinese parts were unavailable, and the US Food and Drug Administration began to investigate how a squeeze on Chinese exports of pharmaceutical feedstock might cause drug shortages.

Dangerous shortages of protective equipment needed for medical staff treating Covid-19 patients are the most serious supply chain symptom of the coronavirus. Some US hospitals are relying on the public to donate N95 masks, or face shields made by volunteers.

Although some companies that still make masks in the US, such as 3M and Prestige Ameritech are expanding capacity, they can’t keep pace with pandemic-spurred demand. Building out new production capacity in a country that spent decades economizing through offshoring is not easy.

Face masks are a low-value, easily shipped item well suited to offshoring in cheaper locales than America. US Department of Health and Human Services figures say 95 percent of surgical masks and 70 percent of tighter-fitting respirators, such as N95 masks, are made overseas. The materials used to make the masks are largely produced overseas, particularly in China, says Hayward, of Monadnock Nonwovens.

“It’s just so easy to buy products or material or machines from China, it’s like the easy button.” Gus Nasrallah, president and CEO, Sharpertek

The emergence of Covid-19 in China made the risks of concentrating production of US health workers’ protective gear in one country painfully clear. The initial outbreak in Hubei province caused a surge in demand for masks inside China, and cut supplies when authorities shuttered factories to halt the virus’ spread. Production of masks has now resumed and companies are expanding capacity, but not much of it has shown up outside China.

One ripple effect has been ringing phones at Monadnock Nonwovens. The company has been swamped with inquiries including from manufacturers in the US, but mostly from elsewhere, such as Asia and South America, who are trying to expand their mask output, and sometimes scrambling to replace materials previously sourced from China.

Hayward says he’s hired more workers and adapted some equipment to produce face mask material, rather than other products, around the clock. The material is made from fine strands of plastic on a machine about 40 feet long and 20 feet high that operates something like a paper mill, churning out nonwoven fabric with tight pores on giant rolls. So far, supplies of the raw plastic have held up.