A man who fell 65 feet while working on a cell-phone tower in Corona de Tucson Tuesday has died, an official said Thursday.

Edward Wallen, 22, was pronounced dead at University Medical Center Wednesday afternoon, a hospital spokeswoman said.

Wallen had been working in the 16000 block of South Houghton Road, near Sahuarita Road, in Corona de Tucson when the incident occurred, according to Todd Cupell, a spokesman for the Corona de Tucson Fire District.

Wallen was working with a partner and was wearing a harness with primary and secondary tethers, but both apparently failed, Cupell said. It was unclear whether it was an equipment failure or operator error.

After his partner called 911, Wallen was flown to University Medical Center.

The Occupational Safety and Health Administration is investigating.