A United Airlines jet taxis along a runway at O'Hare International Airport on October 5, 2006 in Chicago, Illinois.
Mayor Richard Daley isn't worried about the tall grass that surrounds the runways at O'Hare or the debris that's scattered across them.
But Daley said the items noted were "not very significant."
"We take anything very seriously, but it's not jeopardizing travelers coming in and out," Daley said Thursday morning. "If you look at it, anything is a violation, but it's not dealing with the safety of people landing and taking off, we know that."
Officials say a small stone on a runway could pose a risk to a plane that's taking off or landing if its ingested into jet engines or if it pierces a piece of vital equipment.