An inmate from the state prison in Marana suffered life-threatening injuries when he was struck Friday morning by a car on Interstate 10 in Marana, authorities said.

Cary Allan, who turned 47 on Thursday, was airlifted to University Medical Center, said Capt. Adam Goldberg, a Northwest Fire/Rescue District spokesman.

Allan was struck just before 9 a.m. while crews were picking up trash on the shoulder of the interstate, according to the Arizona Department of Public Safety.

Allan's trash bag flew into the westbound lanes near Tangerine Road, said DPS spokesman Bart Graves.

He ran after the bag and was struck by a car, Graves said. The impact left him underneath a state Department of Corrections vehicle, Graves said.

Allan is serving a 27-month sentence for credit-card theft out of Maricopa County, according to online records.