炭素鋼
In 2010, signs of corrosion were reported at the upper regions of the stainless steel surface. Carbon steel in the north leg has been rusting, possibly a result of water accumulation, a side effect of leaky welds in an environment that often causes rain to enter the skin of the structure. Maintenance workers use mops and a temporary setup of water containers to ease the problem. According to NPS documents, the corrosion and rust pose no safety concerns.