Serious corrosion occurs on the inside of tubular/enclosed shapes of weathering steel. Weathering steel will condense moisture inside, or design characteristics will allow moisture to enter the enclosure and accelerate corrosion. There are light poles that have failed, causing fatal consequences, and bridges exhibiting excessive corrosion. • Regardless of moisture level, HDG steel provides corrosion protection both inside and out.Serious corrosion occurs on the inside of tubular/enclosed shapes of weathering steel. Weathering steel will condense moisture inside, or design characteristics will allow moisture to enter the enclosure and accelerate corrosion. There are light poles that have failed, causing fatal consequences, and bridges exhibiting excessive corrosion. • Regardless of moisture level, HDG steel provides corrosion protection both inside and out.