The U.S. relies on China for electronics, clothes, toys and, increasingly, prescription drugs. About 90% of the active ingredients used by U.S. companies in drug manufacturing come from China, which has prompted politicians and public health experts to express concern over potential shortages of common generics.

To date, manufacturing disruptions caused by the novel coronavirus, or COVID-19, haven’t led to reported shortages in the U.S., but the Food and Drug Administration said it’s closely monitoring the situation.

The FDA said earlier this week it was tracking about 20 drugs that are manufactured primarily in China. Depending on the drug, stockpiles lasting weeks, perhaps months, have been warehoused, according to supply chain experts.