With the continued uptick in Covid-19 cases, there has been more demand on the oxygen supply, and hospitals cannot keep up the pace to meet those needs, Donna Cross, who is the senior director of facilities and construction at Premier — a health care performance improvement company — told CNN.

“Normally, an oxygen tank would be about 90% full, and the suppliers would let them get down to a refill level of 30-40% left in their tank, giving them a three to five day cushion of supply,” Cross explained. “What’s happening now is that hospitals are running down to about 10-20%, which is a one to two day supply on hand, before they’re getting backfilled.”

Even when they’re getting backfill, it’s only a partial supply of about 50%, Cross said. “It is very critical situation.”