…..Communication between ambulance crews and dispatchers was equally problematic. The Ambulance Service normally employs two-radio channels during emergency events, with the control room instructing employees as to which channel to use by means of an initial cellular phone call. On July 7, ambulance managers found both channels overloaded owing to the massive number users and the fact that both channels were being routed through a single operator. As a result, only 10 to 15% of radio calls were successful, and requests for additional supplies and paramedics often fell through the cracks. Before long, ambulances at all four sites began running out of the most basic supplies, such as tourniquets and fluids.