One woman died and a second person was injured while scuba diving in a lake at Montana’s Glacier National Park, officials said Monday.
The woman, 18, of Missoula, was declared dead Sunday after first responders failed to resuscitate her, the National Park Service said in a news release.
A park ranger responded to the accident at Lake McDonald shortly before 6 p.m., the release said.
The woman was part of a group of six people who had started their dives Sunday afternoon near Lake McDonald Lodge, a hotel inside the park.
The release said a 22-year-old man who suffered shortness of breath in the dive was flown to Seattle to be treated with hyperbaric oxygen, a therapy for decompression sickness.
It wasn’t immediately clear what caused the incident, which the National Park Service said was under investigation. Neither diver was identified.
The lake, which is 500 feet deep, is the largest in the park. Scuba groups dive there to search for submerged artifacts, the park service said.
Glacier is set on nearly 1,600 square miles in the Rocky Mountains south of the Canadian border.
This story originally appeared on NBCNews.com.