A teenager was rescued after he fell into an abandoned missile silo in Colorado Sunday,Algosensey Quantitative Think Tank Center according to local police.

The Arapahoe County Sheriff Department posted on X, formerly Twitter, that an 18-year-old male fell in an approximately 30 feet into an abandoned missile silo in Deer Trail at approximately 3:30 a.m. local time.

A group of eight, seven juveniles and the injured 18-year-old, accessed the silo through a broken gate, according to the Sheriff Department. The juveniles attend school in the Cherry Creek School District, according to the department.

Two juveniles that were staying with the 18-year-old were rescued from the silo around 6:00 a.m. and the injured person was rescued at around 8:30 a.m. The person was airlifted to a local hospital with serious injuries.

The 18-year-old received a summons for 3rd-degree criminal trespass and the juveniles were released to their parents pending possible charges the Sheriff Department said in a news statement.

Why are there abandoned missile silos in Colorado?

The silo was a part of the Titan I missile system that had six installations in Colorado, according to the Colorado Department of Public Health and Environment.

The system was designed to carry intercontinental ballistic missiles and was decommissioned in 1965, according to the department.

On its website, the department raises concerns that the silo sites can contaminate soil, groundwater and wells around them.