The teens were found at an opening to the caves near Wabasha Street and Plato Boulevard.

St. Paul District Fire Chief Alan Gabriele said someone who works at the building called 911 after spotting the two teens crawling into the cave.

"The people that called were concerned because they've seen what can play out down here before," Gabriele said.

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Each year, he said they have a handful of technical rescues at the caves. Some searches can take hours. Most times, first responders have to use special equipment to hoist people from the passageways.

Gabriele said people trespassing in the caves is an ongoing problem that they are trying to combat.

"They always seem to be able to find the openings," Gabriele said. "You can go in there 10 times and it's safe and then you could go in there the 11th time and it could kill you."

He said once people are inside the caves, they can encounter carbon monoxide poisoning and never know it.

"You can't see it, you can't smell it, can't taste it, but it's there and it will kill you," Gabriele said.

He said the city tries to find those openings to the cave and fill them in with concrete, but environmental factors including erosion create new openings that they can't keep up with.

St. Paul Cave Deaths

While the teens made it out of the cave safely, at least five teenagers have died in that same network of caves over the past few decades.

In April of 2004, rescuers found four teens 600 feet into the caves along Wabasha Street after one of their friends managed to escape and call for help.

Three of them died from carbon monoxide poisoning, but the fourth teenager was able to be rescued and survived.

Twelve years earlier, the bodies of 17-year-old best friends Jill Huntington and Annie Fries were found in one of the caves. The girls suffocated after a fire consumed all the available oxygen.