Here is an article from Forbes about this happening on Monday Forbes Article. 

Remington received text updates from his network about ever-changing quantities of masks in Houston, New Jersey, Miami, Los Angeles and other U.S. cities, along with cities in Canada and the UK. I was astounded by the numbers of masks at these locations. At one point he received an update that 43 million masks were available in New Jersey, in the same time-frame that federal and state leaders were saying in press conferences that they were “scouring the globe” for masks. But the masks in New Jersey, along with many million more, didn’t go to any domestic buyer. Instead, according to the broker, they were all purchased by foreign buyers.

“Most of the masks are leaving the country,” he told me.