A Navy contractor will begin tearing the toxic laminate siding off of Moffett Field's Hangar One on Thursday (April 21), beginning a process that is expected to turn the massive icon into a bare skeleton by early next year.

Scott Anderson, Navy Base Realignment and Closure coordinator for Moffett Field, said in an email that workers were expected to begin to remove siding on the southern end of the hangar, working from the top down.

The corrugated laminate siding contains asbestos, PCBs and lead paint. The panels will be sprayed to keep down dust and will be wrapped in plastic before being transported off site. Anderson said the area will be monitored for air quality during the process.

U.K.-based Amec Environmental has been contracted by the Navy to do the work, and has already conducted an extensive demolition of the hangar's interior buildings.

The siding will be removed in "zones" Anderson said. Panels will be removed from each zone from the top down.

The move will expose Hangar One's well-preserved metal frame to the elements for an unknown period of time. That concerns most who have been involved with saving Hangar One over the years, including Bill Wissel, a member of the Moffett Field Historical Society.

"Without the protective siding, the skeleton structure will be exposed to the elements and will begin to deteriorate pretty quickly," Wissel said in an email."That will mean visual blight, safety concerns. It won't be long before public opinion shifts and there will be an outcry for complete demolition. That's the 'demolition by neglect' concern that everybody has been voicing for the past few years."

Funding to re-skin the metal skeleton has yet to be secured. President Obama's budget proposal for next year includes $32.8 million to allow NASA to restore and reuse the hangar; that sum may be cut in another budget battle with Republicans next year.

Hangar One preservationists had a small victory in March when the Navy announced that it was working with NASA to keep Hangar One's unique wire-reinforced corrugated windows in place during the siding removal. Andersen said that is still not set in stone, but should be resolved by the end of the month. The Navy had previously planned to destroy the windows, which were designed to withstand the explosion of a 1930s airship filled with hydrogen.

The 200-foot-tall hangar was built during the Depression to hold the U.S.S. Macon, an airship used by the Navy between 1933 and 1935. The floating aircraft carrier held several small planes that could be deployed from its belly. It crashed off the coast of Point Sur in 1935.

"Hangar One was assembled by a lot of the same guys who built the Golden Gate Bridge and the Oakland Bay Bridge," Wissel said. "A lot of the same construction companies were used. There is as much history in Hangar One as any structure in the Bay Area, and it can't be replaced."

Wissel added that because of the many proposed uses for Hangar One, including an air and space museum, "Hangar One is one of the few that stands a chance of paying for itself."

Earlier this month NASA Ames sent out a "request for information" to obtain vital information about the contractors who may soon be able to bid on the project. Responses are due April 19. NASA wants new metal siding and roof, and a restoration of the hangar's historic windows. It estimates the project's cost at "over $25 million." A similar request for information was sent to contractors last year but received few responses, and some were incomplete, NASA officials said.