Abstract: A hazard warning system for warning personnel of potential peril within a specific warning zone, the system including a variable, ultrasonic, and/or infra-red directional transmitter directed to focus on and around a specific hazard and a receiver having both audio and visual warning indicators worn by the worker. Workers outside the warning zone or field not receiving the warning are therefore not immunized by visual and audible signals which are not pertinent to their safety. The warning system further utilizes distance measuring circuitry to automatically determine the distance from the transmitter located on an evaluated crane boom to ground or deck. The distance measurement is then micro processed to maintain a prescribed infra-red field around a suspended object regardless of the boom height. A further embodiment utilizes the technology for a portable signal generator apparatus for attachment to a moving load or vehicle, the warning zone or field may be directed and varied in size and range.