In a recent audit of FDA, the Government Accountability Office found that the agency has yet to inspect nearly 1,300 drug manufacturing facilities, mostly based abroad, that are supplying the U.S.

China, the world’s largest manufacturer of active pharmaceutical ingredients, is also the country with the largest number of drug plants that FDA never visited, the audit reports. According to GAO, 243 of the 535 pharmaceutical facilities in China that export to the U.S. (45%) have yet to be inspected.

In India, a major exporter of formulated generic drugs, 33% of the nearly 600 pharmaceutical plants supplying the U.S. have not been visited. And in South Korea, 90% of 171 facilities have yet to be inspected.

GAO does note that FDA inspects more plants abroad than it used to. In 2010, FDA had sent inspectors to only one-third of the drug plants supplying the U.S.; the proportion is now two-thirds. Recently opened FDA stations in foreign countries are increasing the safety of the U.S. drug supply, GAO observes.

GAO does not discuss in detail the risk posed by uninspected facilities. But the agency notes FDA uses a risk-based approach to prioritize which plants, whether in the U.S. or abroad, most urgently need to be inspected.

The public health threat is hard to estimate, but it is likely minimal, says Peter Saxon, president of Saxon International Associates, a New Jersey-based consulting firm that advises foreign drug producers on U.S. drug manufacturing regulations. If FDA has not already inspected the plants, then the facilities likely produce over-the-counter medications, he says.

“There is a risk that the OTC drugs will not work. But if they are adequately tested when they arrive in the U.S., then the risk is low,” Saxon says.

FDA hopes to complete inspecting all drug manufacturing facilities that supply the U.S. in the next three years, GAO notes. But this objective won’t be reached unless the hiring freeze recently instituted by President Donald J. Trump is lifted, Saxon says. Several FDA offices are currently understaffed, he notes.