National Park officials said a 17-year-old sustained "significant" thermal burns to his foot and ankle while hiking in Yellowstone National Park.
According to the National Parks Service, it happened on Monday around Lone Star Geyser, which is located near Old Faithful.
The teen was reportedly hiking in the thermal area when his foot broke through the thin crust, exposing his foot to extremely hot liquid and steam.
“Emergency medical staff responded and transported the patient to a hospital for further treatment,” the park said.
The teen's condition was not described and it is unclear if the teen had wandered off the marked path when his foot slipped in. The NPS did not identify the teen.
“This incident is under investigation and there is no additional information to share,” the NPS said.
According to the agency, this is first known thermal injury at the park this year. A similar case was reported in the area last September.
In that incident, a 60-year-old woman visiting the park from New Hampshire walked off the marked trail with her husband and a leashed dog into a thermal area. She similarly broke through the crust and suffered second and third-degree burns to her lower leg.
According to NPS officials, she had to be flown by helicopter to receive medical treatment. Her husband and dog were not harmed in the incident.


The NPS always recommends hikers stay on marked trails, especially in places such as Yellowstone's thermal areas. Staying on the trail not only protects the plant and animal life and natural features at the park, but it also protects hikers from the potential of deadly danger.
Perhaps the most jarring recent thermal incident at the park occurred back in 2016 when 23-year-old Colin Scott was dissolved after he fell into a thermal spring at the park.
He and his sister walked hundreds of feet off the market trail into the thermal areas. Scott was reportedly hoping to take a dip in a thermal pool that wasn’t dangerously hot, but when he bent over to check the temperature of a prospective pool, he slipped and fell into the nearly 200 degree Fahrenheit water.
Due to the intense heat of the thermal pool, Scott's sister was unable to pull her brother out of the water. Rangers who came to assist her only found Scott's remains in the pool. They were unable to pull his body from the water due to an incoming thunderstorm, and when they returned the next day the acid of the pool had dissolved his body.
Staying on the trail is the best way for hikers to prevent getting horribly burned — or worse.
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