The California Department of Toxic Substances Control (DTSC), pursuant to authority granted under Division 4.5, California Code of Regulations, Title 22, Chapter 20 prepared an addendum to amend the existing Hazardous Waste Facility (HWF) Permit to include additional project activities at the Ducommun Aerostructures Hazardous Waste Facility (Facility). DTSC received a Permit Modification application for the Facility as authorized by the California Health and Safety Code, Chapter 6.5. The Facility is located at 4001 El Mirage Road, Adelanto, CA 93201 and operates under a current Hazardous Waste Facility Post-Closure Permit.
The Facility requests a Class 2 Permit Modification for the replacement of two monitoring wells at the Facility. The Facility proposes the replacement of two wells to address declining water levels at detection monitoring well B101 and point of compliance well B102. Two replacement wells (B105 and B106 respectively) are proposed to be installed. The proposed modification does not include any significant changes to the permit or any significant physical changes to the Facility.
The property covers about 120-acres located in Adelanto, California and includes a 2.25-acre former percolation pond and 0.75-acre surface impoundment. The Facility refers to the portion of the property related to the former percolation pond and surface impoundment. Closure of the Facility included removal of all free liquids, stabilization of the residual solids, placement of the stabilized wastes back in the surface impoundment, and placement of a protective cap over the surface impoundment and former percolation pond as a single unit. Closure activities commenced in November 1989 and were certified complete by DTSC on June 22, 1990. There will be ground disturbing activities and temporary construction activities related to the construction of the groundwater monitoring wells. Pre-construction surveys will be completed prior to construction to ensure no biologically sensitive species will be affected in the construction of the groundwater monitoring wells