A recently completed project at Chicago's O'Hare Airport makes an interesting case study in the application and design of plume abated cooling towers. Expansion of the airport had resulted in cooling towers being located between the FAA control tower and one of the taxiways. The visible plume from these towers was obstructing the vision of pilots on the taxiway, and blocking the line of sight between the control tower and the taxiway. The solution to this problem was to build a new plume abated cooling tower at the site. Design/plume abatement requirements, site restrictions, maintenance and operational flexibility were a few of the many issues involved in the planning and implementation of this project.