On the website of the Food and Drug Administration, there’s a page where the agency lists drugs that are in short supply in the United States. Last week, there were 90 entries on the list: antibiotics, drugs for anesthesia, compounds to light up veins and organs for imaging, immunosuppressives to prevent organ rejection, tube-feeding solutions, sedatives. For every type of medical problem, an important drug is off the market or in short supply—and this is routine.

In the fall, after Hurricane Maria tore through Puerto Rico, something new joined the list, not a drug but a category of medical equipment: bags of sterile salt water. When the territory’s electrical grid went down, it took out several plants that make bagged saline for US manufacturer Baxter International. Few noticed at first, until this winter’s flu season got bad. One of the first things you do when someone arrives at a hospital weak and feverish is plug them into a quart bag of saline to rehydrate them. Another might be giving them drugs through a smaller bag hooked to an IV drip. In many hospitals, both were suddenly rationed.

Missing IV bags and missing pharmaceuticals seem like unrelated problems, a temporary disruption layered on top of a longstanding problem. But in fact, they are unavailable for the same reason. The United States has allowed the manufacturing of most of its drugs and medical devices to drift offshore, at the end of long, thin supply chains.

If a single hurricane can break one of those chains, undermining the delivery of medical supplies that Americans need every day, imagine the impact of a border-crossing epidemic or a regional military conflict or a natural disaster like the volcanic eruption that shut down most of Europe’s airspace in 2010.

This ought to be a matter of national security. So far, it’s not.

Most people don’t have contact with the ongoing drug and IV shortages, so they can come as a shock. “My wife’s nurse had to stand for 30 mins and administer a drug slowly through a syringe because there are almost no IV bags in the continental US anymore,” Ben Boyer, a former TV executive who lives in San Diego and whose wife is undergoing chemotherapy for brain cancer, tweeted on December 28.

To physicians, though, it’s hellishly normal. “I am on staff at several different hospitals in western Pennsylvania, and there are weekly emails: These are the fluids on shortage, these are the ones in stock,” says Amesh Adalja, an infectious-disease physician and a senior scholar at Johns Hopkins University’s Center for Health Security. “I think most people think of normal saline as something like, well, water, that you can get anywhere. The average physician doesn’t know where it came from or what the brand names are.”

As it happens, Adalja has been thinking about where things come from for a while. In 2012, he noticed that the drugs that were scarcest in hospital pharmacies were things that would be critical to have in a national emergency: antibiotics for bioterrorism agents, for instance, or antivirals for severe flu. Working with several colleagues, he tried to figure out why—and discovered that most of the drugs he wanted to prescribe were no longer made in the United States.

The last US factory making penicillin closed in 2004, he found. Only 10 percent of the generic drugs used in this country are made here. Four-fifths of the active ingredients in American pharmaceuticals come from somewhere else, mostly India and China. If anything disrupted delivery of a critically needed drug—a process line collapsing in a factory, a typhoon fouling the path of container ships—supplies would run short, the manufacturer would be far out of US jurisdiction, and there would be no domestic alternative.

"We’re going to have the big pandemic, or something close to it, and other countries will stop shipping us masks, and health care workers will feel unprotected."

“People don’t think of infectious disease preparation as part of national security,” Adalja told me. “But how much trouble would we be in if we had an anthrax attack at the same time as a Cipro shortage? Supply shocks make us vulnerable.”

Supply shocks aren’t only caused by natural disasters. As FDA commissioner Scott Gottlieb wrote at Forbes in 2010—after leaving the Bush-era FDA and before joining the Trump administration—Canada and Australia prevented flu vaccine manufacturers in those countries from filling US vaccine orders in the 2009 H1N1 influenza pandemic, effectively nationalizing the shots. Those orders represented 5 percent of what the US had contracted to buy that year—but by a stroke of fortune, the 2009 pandemic was so mild that most of the vaccine went unused, and the shortage was not noticed.

At the same time that Adalja and colleagues were researching drug shortages, President Barack Obama signed an executive order telling US-based manufacturers that allowing drugs to run short would not be tolerated. A few months later, the Association of State and Territorial Health Officers and the Department of Health and Human Services drew up guidelines to help the health care industry cope with shortages, including guidance on how to use expired drugs or veterinary formulas if things got desperate.