Three people were injured Saturday in two separate but related ATV crashes in St. Louis County.

First responders were called to an ATV crash with injuries near a park on Memorial Drive in Buhl just after 4 p.m. Saturday, according to the Sheriff's Office.

An ATV speeding west on Memorial Drive had veered into a grassy ditch area, become airborne, landed and flipped end over end, ejecting a 21-year-old Virginia man and a 19-year-old Cloquet woman, authorities said.

As first responders were tending to them, they were alerted to another ATV crash near the intersection of Memorial Drive and Jefferson Street. A 25-year-old man had turned around in an attempt to return to the first crash to help out when his ATV rolled, pinning him underneath. Neighbors provided emergency aid until first responders could get to that crash.

The man in the first crash was airlifted to St. Luke's Hospital in Duluth and later to a Twin Cities hospital with life-threatening injuries, authorities said. The woman from the first crash and man injured in the second one were taken to Fairview University Medical Center-Mesabi in Hibbing, where they are being treated for noncritical injuries.

The victims' names have not been released.

Speed and alcohol appear to have been factors in the crashes, the Sheriff's Office said.