But the U.S. is woefully unprepared to address even minor disruptions in the supply of these drugs.

“Medicines can be used as a weapon of war against the United States,” Rosemary Gibson, a senior adviser on health care issues at the bioethics-focused Hastings Center and co-author of “China Rx: Exposing the Risks of America's Dependence on China for Medicine,” told lawmakers last month. “Supplies can be withheld. Medicines can be made with lethal contaminants or sold without any real medicine in them, rendering them ineffective.”

A watchdog report last month by the U.S.-China Economic and Security Review Commission and a recent congressional hearing warn that China hopes of surpassing the United States as the world’s biggest producer of pharmaceutical products.

Last year, China accounted for 95 percent of U.S. imports of ibuprofen, 91 percent of U.S. imports of hydrocortisone, 70 percent of U.S. imports of acetaminophen, 40 to 45 percent of U.S. imports of penicillin and 40 percent of U.S. imports of heparin, according to Commerce Department data.

In a letter to health chiefs last year, Senate Finance Chairman Chuck Grassley cited reports claiming 80 percent of active pharmaceutical ingredients are produced overseas, mostly in China and India.

In a rare high-profile public comment, one former central bank adviser suggested that China could curb its exports of antibiotics to the United States as a trade war retaliation tool.

“We are at the mercy of others when it comes to computer chips, but we are the world’s largest exporter of raw materials for vitamins and antibiotics,” Li Daokui, a professor of economics at Tsinghua University, said in March 2019 while speaking at the National People’s Conference.

“Should we reduce the exports, the medical systems of some western countries will not run well,” he added.

The number of FDA import alerts — which can lead to a complete blocking of flagged products from entering U.S. ports — regarding Chinese companies has steadily risen, from 19 in 2016 to 23 in 2017 and 28 in 2018.

POLITICO NEWSLETTERS Morning Trade A speed read on global trade news — weekday mornings, in your inbox. Sign Up Loading By signing up you agree to receive email newsletters or alerts from POLITICO. You can unsubscribe at any time. This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Gibson noted that a single factory in China made the active pharmaceutical ingredient for a common blood pressure medicine, valsartan, that was found to contain a cancer-causing chemical that has been used to make liquid rocket fuel.

Some of the companies on the FDA's warning list also benefit from generous state subsidies. In general, successive U.S. governments have railed against this sort of behavior from China, one of the driving forces behind the 17-month trade war.

Zhejiang Huahai Pharmaceutical (ZHP), producer of the contaminated valsartan, disclosed in a 2018 annual report that it had received $44.4 million (312 million yuan) in government subsidies. Over the first half of this year, it had received an additional 92 million yuan in state funding.

Despite the contamination incident, ZHP still leads the U.S. market share in 10 of its product lines, it said, including drugs used to treat high blood pressure and Alzheimer’s disease.

When FDA inspectors visited Henan Lihua Pharmaceutical’s facilities in the city of Anyang two years ago, they found “significant deviations from current good manufacturing practice.” Among the red flags were product release forms stamped in advance to speed up warehousing processes. Its parent company was also a generous recipient of Chinese subsidies for research, renovations and infrastructure last year.

There aren’t enough FDA personnel to conduct on-site inspections in China, adding to the worries of many in Congress. But a shortage of some critical medicine has prompted the FDA to allow the sale of some Chinese-made drugs that could pose a safety risk, rather than be caught without any supply.

“If we have quality problems at a plant, we have to make a medical decision” about the consequences of banning the use of the drug, Janet Woodcock, director of the FDA’s Center for Drug Evaluation and Research, testified in October. “It puts us in a difficult position.”

Lawmakers also say they are concerned about a growing dependence on China for imports of active pharmaceutical ingredients (APIs) — the actual medicine contained in a pill, capsule, or shot.

The FDA estimates that 13 percent of the world’s API production facilities are in China, compared with 28 percent in the United States. About 26 percent are in the European Union and 18 percent in India.

There is concern the actual amount of active pharmaceutical ingredients coming from China is much higher than those figures suggest. An FDA spokesperson in Washington said the United States imported over 6,000 APIs from China in the 2019 budget year that ended in September.

The FDA in Beijing declined to comment on the supply risk.

But the China Chamber of Commerce for Import & Export of Medicines & Health Products states that China is the world’s largest producer of generic drugs. More than 90 percent of China’s 4,300 API and pharmaceutical manufacturers produce generic products. As with other industrial sectors, China’s strength is in its scale.

“Thanks to its low-cost structure, China is already a dominant supplier of APIs to a number of countries, including the U.S.,” said Knut Slatten, senior analyst at Moody’s Investors Service. “Companies don’t generally disclose data on this, however, up to 90 percent of drugs by volume consumed in the U.S. are generic drugs.”

Sen. Mitt Romney (R-Utah) called for an examination of U.S. dependence on imports of active pharmaceutical ingredients and finished drugs from China. | Rick Bowmer/AP Photo

A high-profile group of senators, including Democratic presidential candidate Elizabeth Warren (D-Mass.) and Sen. Mitt Romney (R-Utah), this month called on Defense Secretary Mark Esper to examine the national security risks of U.S. dependence on imports of active pharmaceutical ingredients and finished drugs from China.

Previous incidents of contaminated drug shipments from China have also prompted lawmakers to ask for a staff-level briefing by Dec. 20 to answer a number of questions, including what steps the Defense Department has taken to protect the medical supply.

"Millions of Americans, including service members, rely on drugs to stay healthy — yet the United States imports a significant portion of these drugs' components from China," the senators, joined by Sens. Tim Kaine (D-Va.) and Tom Cotton (R-Ark.), said in a letter.

The lawmakers, however, point out that such reliance on China on “a geopolitical rival for critical drugs presents a clear risk to our national security, even more so in a period of heightened tensions."

Generic drug companies believe critics such as Gibson and the U.S.-China Commission are overstating the risks. Last year, the U.S. imported $115 billion of finished pharmaceutical products, with just $1.5 billion coming from China.

If heart patients stop taking their drugs because of concern that they may come from China, “that's going to be very detrimental to the American public health,” said David Gaugh, senior vice president for sciences and regulatory at the Association for Accessible Medicines, a generics drug industry group.

Some who follow the Chinese sector say such concerns are misguided because of numerous other nations that provide medicines.

“I don’t think the U.S.’ concerns are particularly tenable, as the U.S. also imports a lot antibiotics from India. The U.S. imports a lot of APIs, and if the FDA conducts annual inspections on these factories, then why should the U.S. worry?” asked Frank Wang, a Shanghai-based analyst for Capital Securities, which is based in Hong Kong.

Zhu Jianyun, deputy secretary-general of the supply chain division at the China Association of Pharmaceutical Commerce, put the blame on manufacturing companies rather than U.S.-China policy.

“I know the U.S.’ generic drug manufacturing capacity is relatively weak, but they decided to relocate their production lines to China and some southeastern Asian countries to save on costs, so they cannot simply say China is a threat just because they wanted to save the cost,” Zhu said.

The U.S.-China Economic and Security Review Commission, a watchdog panel Congress created, in November laid out a set of recommendations aimed at discouraging U.S. companies from importing Chinese-made medicines.

Those include mandatory country-of-origin labels for APIs used to make drugs and making importers liable “for any health risks incurred by consumers in the event the product is proven unsafe due to contamination, mislabeling, or other defects.”

It also recommended steps to increase domestic pharmaceutical production, which has fallen in recent years as more and more manufacturers have moved production to lower-cost markets like China and India.

Senate Minority Leader Chuck Schumer called on the Government Accountability Office to investigate the capability of the United States to manufacture finished pharmaceutical products and active pharmaceutical ingredients. | Drew Angerer/Getty Images

“Our biggest vulnerability is overdependence and single source of supply,” said Mike Wessel, a longtime member of the U.S.-China Commission. “For critical products like antibiotics as well as life-sustaining drugs like blood pressure medicine, China, directly or indirectly, is the major or potentially sole supplier of those products to the U.S.”

Senate Minority Leader Chuck Schumer last week called on the Government Accountability Office to investigate the capability of the United States to manufacture finished pharmaceutical products and active pharmaceutical ingredients.

“I am greatly concerned by the strategic vulnerability created by our reliance on China, a strategic adversary, for the APIs used to manufacture a very wide range of life-saving drugs that are vital to our healthcare system,” Schumer said in a letter.