A fire broke out in an industrial park near O'Hare Airport Tuesday morning, sending thick plumes of smoke into the sky. The fire started around 7 a.m. in a semi-trailer near the west end of O'Hare's airfield in the industrial park near Pan Am Boulevard and United Lane in Elk Grove Village. The fire spread to at least one other semi-trailer that was nearby in the transportation bay. Several streams of water were being put on the fire. Aviation officials have not said if any flights have been impacted. There is no ground stop at O'Hare as crews work to extinguish the fire. No injuries have been reported. The cause of the fire is unknown.