An MD80 Flight Crew rejected their takeoff when the forward cargo door opened at approximately 90 kts on the takeoff roll.

Narrative

We started our takeoff roll and everything was normal until approximately 90kts. At that point I observed a 'FWD CARGO DOOR' annunciator. Along with the annunciator; I heard a verbal warning from an Airport Operations Agent stating our cargo door was not secured properly. The Agent was in a vehicle beside the runway waiting to cross and on Tower frequency. I immediately aborted the takeoff. Because of the heavy braking and reverse thrust a wheelchair and a couple boxes fell out of the compartment and onto the runway. The Agent retrieved the items and met us at the gate. No damage was done to the aircraft; runway or injuries to any passengers or personnel. From the flight deck; there was no indication of a problem until the takeoff roll was commenced. I believe the decision to abort was warranted and performed to company standards. The entire crew performed professionally at all times. In the future; I would like to see more attention taken by ground personnel to ensure the aircraft is safe for departure and doors are secure. I also will be asking more questions and ensuring more communication is achieved.