PA-28 Cherokee/Archer/Dakota/Pillan/Warrior
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 7.9
ATC Issue All Types; Conflict Ground Conflict; Less Severe; Ground Incursion Runway
Air Traffic Control Provided Assistance
Human Factors
I was working Ground Control; and our Supervisor was training on Local 1. I had an aircraft call me clear of Runway 28L at Taxiway G1 (Aircraft X). I immediately noticed he was not clear of Runway 28L and appeared his tail was partially over [Runway] 28L. I alerted Local Control as Aircraft Y was departing Runway 28L and airborne as they passed Aircraft X. I then taxied the aircraft to transient ramp. The trainee on LC1 did not observe the issue until I pointed out and had an aircraft on takeoff roll and airborne before noticing the event. The Supervisor was involved and notified of the event when it happened. I estimate 10/15ft lateral separation; and 50ft (at the most) vertical separation when the event occurred. I recommend recurrent training for the trainee involved and/or emphasis on scan especially when issuing departure/landing clearances. I believe the lack of scan and tower cab awareness led to the event happening. This trainee is near their max hours; recommend an evaluation to see whether or not they can truly make it at ZZZ.
Ground Controller reported a runway incursion due to developmental on Local not scanning runway to ensure arrival was clear of runway.