After looking at the HAER pages for this bridge I found some new information. The East span was not a Columbia Bridge Works span, but was built in 1914 according to the documentation. The great 1913 flood destroyed the original CBW East span and it was replaced the following year with a Pratt through truss built by the Mt. Vernon Bridge Company. This East span was either lost in another flood or removed for a different reason. The West span was able to avoid disaster until man brought about it's demise.