CHICAGO, July 2 (Xinhua) -- Air-traffic controllers in the Chicago region may be battling fatigue on a regular basis due to short turnarounds between shifts and a push to work overtime, said a report Thursday.

    Most controllers at O'Hare International Airport as well as at two nearby Federal Aviation Administration radar facilities are scheduled to work at least one shift each week in which less than 10 hours of potential rest is scheduled between shifts, according to the report by the U.S. Department of Transportation.

    Such quick-turns typical among controllers "offers minimal opportunity for sleep when the time required for commuting, eating and other necessary daily activities is taken into account," the report said.

    In addition to working rotating shifts with progressively earlier starting times, some controllers are providing on-the-job instruction to controller trainees. Training the developmental controllers requires an especially high level of concentration and it produces extra stress because the training involves handling live traffic, it said.

    The assessment at the facilities in Chicago area was requested by U.S. Sen. Dick Durbin based on evidence that controller fatigue has figured prominently in errors that could have led to collisions between airplanes on runways at the nation's busiest airports.

    The report said the fatigue factors it found at Chicago's O'Hare International Airport and other air-traffic facilities in the Chicago region probably also exist at other large radar centers across the country.

    The report issued recommendations to the federal authorities to mitigate risks that could jeopardize safety.