(KMOV) -- They are not easy to see, but they are there. The streaks along the legs of the Gateway Arch. Park Service officials don't know what to make of it. The arch is after all made of stainless steel, yet there seems to be stains. An engineering consultant is looking into the problem.
Could it be dirt or grime from pollution? Maybe streaks left over from the construction cranes in the 60's? Any number of things could be the cause. Because of it's height and steep angles, no one can just go up there with a power washer and give it a good cleaning.
As it stands now, park service officials don't believe this is any cause of concern that the arch is wearing down. After all it was designed to last a thousand years.