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Hazardous Substances at Moffett Field’s Hangar One: Challenges and Opportunities

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Steve Williams
Steve Williams

Hangar One at Moffett Field was added to the Superfund list in 1987 due to soil and groundwater contamination from trichloroethylene (TCE). In 2003, polychlorinated biphenyls (PCBs) were found to be leaking from Hangar One into the wetlands. The Navy removed the siding and roof of Hangar One and coated the structural frame to address the PCB contamination. Long-term management of residual contamination at the site and mitigation of vapor intrusion will require ongoing inspection, maintenance, and monitoring efforts led by the Navy and EPA.

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Hazardous Substances at Moffett Field’s Hangar One: Challenges and Opportunities
Moffett Field added to “Superfund” List in 1987 because of TCE Contamination
In 2003 Hangar One found to be source of PCBs in Moffett wetlands
Navy’s proposal to demolish hangar blocked by public outcry
So Navy removed siding/roof and coated the frame
Long-Term Management Plan requires inspections of coating on • Structural steel frame (excluding the top and bottom sides of the mezzanine deck). • Concrete Masonry Unit (CMU) walls surrounding the six electrical vaults. • CMU walls surrounding the former hazardous materials storage room. • CMU walls that were part of the former toilets. • Door operating mechanisms (trucks/bolsters, motor housing, electrical vaults, and drive gear housing).
and sampling of stormwater and sediment
EPA leading effort to replace pump-and- treat with new groundwater remedies
Reuse will require mitigation of vapor intrusion
Aerated floor can be installed with new concrete slab to prevent vapor intrusion
Existing tunnel and any new utility corridors must be sealed
and air monitoring will be necessary after re-covering
The Navy is responsible for inspection and maintenance of Hangar One’s epoxy coating as well as stormwater and sediment sampling. The Navy is also responsible for vapor mitigation in existing buildings. But it doesn’t want to be.
Any lessee who attaches a new roof/siding and/or modifies the hangar floor is likely to incur Superfund liability.
SOLUTION: Navy pays lessee to take responsibility for long-term management of residual contamination as well as vapor mitigation, based upon Navy’s projected costs. Navy can’t just walk away. Negotiations among lessee, NASA, Navy, and EPA are essential.

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Hazardous Substances at Moffett Field’s Hangar One: Challenges and Opportunities

  • 1. Hazardous Substances at Moffett Field’s Hangar One: Challenges and Opportunities
  • 2. Moffett Field added to “Superfund” List in 1987 because of TCE Contamination
  • 3. In 2003 Hangar One found to be source of PCBs in Moffett wetlands
  • 4. Navy’s proposal to demolish hangar blocked by public outcry
  • 5. So Navy removed siding/roof and coated the frame
  • 6. Long-Term Management Plan requires inspections of coating on • Structural steel frame (excluding the top and bottom sides of the mezzanine deck). • Concrete Masonry Unit (CMU) walls surrounding the six electrical vaults. • CMU walls surrounding the former hazardous materials storage room. • CMU walls that were part of the former toilets. • Door operating mechanisms (trucks/bolsters, motor housing, electrical vaults, and drive gear housing).
  • 7. and sampling of stormwater and sediment
  • 8. EPA leading effort to replace pump-and- treat with new groundwater remedies
  • 9. Reuse will require mitigation of vapor intrusion
  • 10. Aerated floor can be installed with new concrete slab to prevent vapor intrusion
  • 11. Existing tunnel and any new utility corridors must be sealed
  • 12. and air monitoring will be necessary after re-covering
  • 13. The Navy is responsible for inspection and maintenance of Hangar One’s epoxy coating as well as stormwater and sediment sampling. The Navy is also responsible for vapor mitigation in existing buildings. But it doesn’t want to be.
  • 14. Any lessee who attaches a new roof/siding and/or modifies the hangar floor is likely to incur Superfund liability.
  • 15. SOLUTION: Navy pays lessee to take responsibility for long-term management of residual contamination as well as vapor mitigation, based upon Navy’s projected costs. Navy can’t just walk away. Negotiations among lessee, NASA, Navy, and EPA are essential.