Recently, mysterious stains have appeared on the surface of St. Louis’ Gateway Arch, which are thought to be by the monument’s original construction, residue accumulation and graffiti. But the dirt and stains won’t be cleaned away, as an official for the National Park Service has stated that an overall cleaning of the monument is “not feasible.”
The report, completed by the Chicago firm Wiss, Janney, Elstner Associates, is the culmination of several decades of research into stains appearing on the monument’s stainless steel skin.
In October, the firm sent climbers to rappel down the 630-foot Arch’s legs to get samples and a close-up look. The samples were then sent for testing. The tests showed the stainless steel is in “serviceable condition, without significant structural distress or deterioration.” The Arch is structurally sound, according to the report and several different cleaning treatments were suggested.
It stated, “Cleaning trials were successful in reducing some of the superficial corrosion staining and provided a wide range of passivation and refinishing options for the stainless steel.” But Frank Mares, the Jefferson National Expansion Memorial’s deputy superintendent, said in an interview that a top-down cleaning would be too difficult. “We’re not sure there is a practical and feasible way to do the entire monument,” Mares said. “It was a suggestion and recommendation, but that won’t be able to happen.”
The report also recommended increased security around the monument’s base, which has been touched by vandalism and graffiti. “We are satisfied with the extent of the research, the completeness of this report, and are ultimately quite pleased that the monument is, in fact, in great shape,” Mares said in a written statement. The Arch has never been cleaned since it was topped off in 1965.