To treat more than two dozen tourists severely burned in a volcanic explosion earlier this week, doctors in New Zealand are rushing to obtain a unique medical export from the United States.

The doctors are buying nearly 1,300 square feet of human skin.

At a briefing on Thursday in Auckland, health officials outlined the desperate task before them. The volcanic explosion on White Island left 27 visitors with severe burns, some covering up to 95 percent of their bodies. Twenty-two are in critical condition.

Surgeons already have been operating nonstop on these patients, because many of the injuries were worsened by chemicals and gases in the eruption. But there is not enough human skin in New Zealand for surgeons to treat all of the injuries they are seeing.

“The health system is equipped to respond to this, but in terms of the size, these are very unusual events,” said Dr. John Kenealy, clinical director of surgery at Counties Manukau in New Zealand. “The number of burns is unprecedented.”