U.S. companies continued their massive sell-off of medical masks overseas throughout March, well after the coronavirus began infecting Americans and draining hospitals of critical supplies and even as White House officials raised red flags, a USA TODAY investigation found.

America exported more protective masks — including disposable surgical masks and N95 respirator masks — this March than in any other month in the past decade. In all, $83.1 million worth of such products were sent from the United States to the rest of the world, according to an analysis of the latest U.S. Census Bureau trade data for the export category that includes textile-based protective masks.

March’s total export figure surpassed the previous high of $74.3 million set in February, when many of the masks went to China. And it far exceeded the average monthly shipment value of $53.3 million over the past decade, USA TODAY’s analysis found. The data shows only monthly totals and does not allow for a daily breakdown of shipments or companies.