The iconic Hangar One at Moffett Field is slated to undergo a five-year restoration effort that would eventually rehabilitate the former airship depot for future use. Under a new set of plans publicized this week, Google's subsidiary Planetary Ventures is proposing an extensive, $157 million operation to purge a variety of toxic compounds and reskin the hangar's 200-foot-tall steel frame.
The announcement of a cleanup plan has been a long time coming. In 2015, Google signed a 60-year lease with NASA Ames to take over 1,000 acres at Moffett Field. As part of that deal, Google officials pledged to eventually restore the Hangar One by cleaning up its structure and reskinning it with new siding.
But ever since the lease was inked, Planetary Ventures officials have been sparse on details for how and when this cleanup would begin. The company issued occasional updates, mostly saying they were continuing to study the project and test out different cleanup methods.
The new 300-page technical report lays out in intricate detail how Planetary Ventures would undertake the complex task of removing lead, asbestos and other harmful chemicals from the massive hangar structure. About 15 years ago, environmental studies determined that these hazardous materials were embedded in Hangar One's paint and siding, and these toxins may have been flaking off and leaching into the nearby baylands.
At the time, a full rehabilitation of Hangar One was estimated to cost around $40 million. Based on that daunting price, U.S. Navy officials in 2011 decided to remove the thousands of panels of corrugated laminate siding covering the hangar, leaving it as a bare steel skeleton. In a controversial move, they also proposed tearing down the structure, describing it as the most sensible plan in light of the immense costs of a full cleanup.
When Google agreed to shoulder Hangar One's restoration as part of the lease, the move was celebrated as a huge victory for an impassioned cohort of historic preservationists who regarded it as an irreplaceable relic of Moffett Field's military days. Those advocates will likely be very happy to hear that the cleanup plans are finally moving forward, said Mountain View resident Greg Unangst, who chairs the Moffett Field Restoration Advisory Board.
"People will be amazed at the cost, but they'll be pleased to see that this is finally happening," he said. "Up to this point, a lot of people were getting frustrated over the apparent lack of action."
The new report, prepared by the Burlingame consulting firm EKI Environment & Water, examined three options for Hangar One. One option, to do nothing at all, was included only as a baseline for comparison. A second alternative called for recoating the entire structure in a new layer of protective paint that would prevent lead and other substances from chipping off. Going that route and later reskinning the hangar would cost a total of $115 million, but it wouldn't do much to reduce the toxic materials contained in the structure, according to the report.
The authors of the report threw their support behind a third option that would involve something akin to sand-blasting the structure to remove its toxic coating. Under this plan, teams of workers would blast the hangar's steel framework with a copper slag powder that was determined to be the most effective substance to use. To fully clean approximately 1.8 million square feet of surface area on the hangar, the consultant team estimates they will need about 5,000 tons of copper slag to do the job, and occasionally they may need workers to go at certain spots with chemical stripping solvents or hand tools.
The project also calls for a plastic covering to be wrapped around all the exterior of Hangar One and a rubber mat to be spread along the base to prevent hazardous wastes from drifting away. In total, the project expects to collect about 6,500 tons of hazardous waste that will be taken to an off-site disposal facility. This cleanup phase is expected to cost more than $85 million, not counting subsequent expenses for reskinning the structure.
Given Hangar One's massive size, the rehabilitation project would require a vast quantity of scaffolding to be built all around the interior and exterior, at an estimated cost of $54 million. In addition, seismic retrofits to the hangar are expected to run about $17 million.
While Google is showing its commitment to saving Hangar One, the company's longer-term intentions for the hangar remain a total mystery, Unangst said. Initially when the lease was signed, the company indicated it would use the site for research and development of robotics and aviation technology. A Google spokesperson said any future use would adhere to the historic status of the location.
While work on Hangar One has been in a holding pattern for years, Google has made some headway in rehabilitating the aging Hangars Two and Three. These twin 171-foot-high structures, both built in the 1940s, today have structural damage as well as toxic contamination in their foundation.
About two years ago, work crews began fixing the giant wooden doors on both sides of Hangar Two. Around the same time, news reports indicated that Hangar Two was being used as the staging grounds for Google co-founder Sergey Brin's side project to build a modern-day zeppelin. According to people involved in the project, the airship was intended to deliver aid cargo to remote locations as well as used for luxury travel.
The fate of Hangar Three is less certain. Structural engineers previously reported that the wooden framework was sagging in certain areas. From his talks with people working at the site, Unangst said he had been told that Hangar Three could be too dilapidated to save.
"There's a possibility that Hangar Three is not salvageable," he said. "From what I know, it's collapsing. It's a wooden structure that's starting to give way. When they fix one section, the next section fails."
A Google spokesman told the Voice that Planetary Ventures and NASA are still evaluating the structure of Hangar Three.
The new cleanup plans put together by Planetary Ventures are currently under a 30-day review period for feedback from the U.S. Environmental Protection Agency and the San Francisco Bay Regional Water Quality Control Board.
If the plans proceed as scheduled, the cleanup effort would start next year with an expected completion date sometime in 2023. At that time, Planetary Ventures officials expect to begin "recladding" the hangar, covering the steel framing with new paneling.
In a statement, U.S. Rep. Anna Eshoo hailed the new plan to restore Hangar One as a crucial next step.
"The Hangar symbolizes the pride and potential of our local community," she said. "I'm so pleased my work along with my California Congressional colleagues, federal partners, advocacy groups, businesses, and historic preservation associations has secured a bright future for the landmark."