Hawthorne Municipal Airport Hangars Project

The Department of Toxic Substances Control approved an Interim Measures Workplan to support the installation of a passive vapor intrusion mitigation system, permanent soil vapor wells, and a contingency soil vapor extraction system. These measures are intended to minimize the potential migration of volatile organic compounds in soil vapor, monitor subsurface soil vapor conditions, and install contingency soil vapor extraction piping as part of the construction and redevelopment of two hangar structures at the Hawthorne Airport. The Hawthorne Municipal Airport Hangars Project Initial Study Mitigated Negative Declaration (MND) was certified by the City of Hawthorne on January 30, 2026. The final MND analyzed the construction of 13 new aircraft hangars at four designated sites within the Hawthorne Airport. The project also includes demolition of six buildings totaling 18,000 square feet, removal of 55,000 square feet of impervious surfaces, and replacement with new pavement and airfield safety enhancements. The hangars will range from 2,500 to 25,300 square feet and incorporate modern fire suppression systems, energy-efficient lighting, and seismic reinforcements. Construction will occur in phases from June 2025 to late 2028. DTSC utilized information and analysis in the final MND to support a determination regarding the type of environmental document required for the IMWP, as provided by Sections 15162, 15163, and 15164 of the CEQA Guidelines. An Addendum was prepared that considered the environmental impacts analyzed in the final MND. The Addendum focuses on determining whether the project activities associated with the IMWP would increase the severity of previously identified impacts or result in any new impacts not considered in the final MND.