Aerojet Chino Hills Clean Up
The California Environmental Protection Agency entity in charge of overseeing the Aerojet Chino Hills, the Department of Toxic Substances Control, maintains an EnviroStor website that has numerous documents, descriptions and data. The DTSC’s Aerojet Chino Hills Facility website describes the facility:
Facility History
Entered 9/17/07 – Inactive Facility. The Aerojet Chino Hills Facility consists of about 800 acres located in an undeveloped area of the City of Chino Hills. The Facility was a munitions assembly and test facility that operated from 1954 until the facility closed in November 1995. Ordnance assembled and tested at the Facility included high explosive incendiary (HEI) rounds, armor piercing incendiary (API) rounds containing depleted uranium and a wide variety of fuzes. Tear gas canisters were also produced at the facility. Most of the ordnance was small (20 mm to 30 mm size range) although rounds up to 105 mm have been found during ordnance sweeps at the facility. Solid rocket motors containing perchlorate were tested in one area of the facility. During the late 1960′s and early 1970′s the Facility conducted research and development of munitions involving proprietary organic chemicals related to mustard gas, organophosphates and glycolate esters. This testing was done in an enclosed chamber at the facility. As part of this research and development, environmental testing of organophosphate chemicals was conducted on plants in a greenhouse.
Two projects are currently underway at the facility. The Open Burn/Open Detonation Unit, which operated from 1965 through 1992, is regulated under Interim Status and is currently undergoing closure. The Closure Plan was approved in December 1993, and closure field work began in 1994. Field work was completed in December 2006, and the Closure Certification Report was submitted in March 2007, and is currently under review.
The second project is Corrective Action for closure of the entire facility. A consent agreement was signed in 1994 and RFI field work was conducted from June 1995 through November 1998. Twenty-nine solid waste management units and areas of concern were identified during the RFI, of which 10 required corrective measures. Constituents of concern include explosive chemicals (e.g. RDX, HMX etc.), perchlorate, uranium and ordnance. A health risk assessment for chemical contamination concluded that the site did not pose a risk to the offsite community, and that several of the 10 areas required cleanup based on chemical contamination. The Selected Remedy included excavation and off site disposal of soil contaminated with explosive chemicals, excavation and disposal of a limit quantity of material contaminated with tear gas residue, and excavation and sifting of soil for ordnance at several areas of the facility. The Proposed Remedy was public noticed in spring 1999 and was approved in November 2000. As part of the Remedy approval, the Facility was required to conduct additional site investigation for perchlorate and explosive chemicals, prepare a health risk assessment to assess noncancer effects of depleted uranium, and develop a Community Ordnance Education Plan. Most of the Remedy has been implemented, and DTSC approved the depleted uranium health risk assessment in September 2004. The Corrective Measures Completion Report, which documented the cleanup efforts, was submitted in November 2003. DTSC reviewed this report, and required additional investigation.
The workplan for this work was submitted in May 2006, and approved in August 2006. Field work has been completed, and the report documenting the field work was submitted in November 2007. DTSC provided comments on this report in March 2008. Aerojet has also conducted surface and subsurface water sampling to monitor the levels of perchlorate and explosive chemicals remaining after implementation of the Corrective Measures. Reports have been submitted in 2005, 2006 and 2007, and DTSC has previously reviewed the 2005 and 2006 reports. . DTSC provided comments on the 2007 report in April 2008.
In July 2004, DTSC approved the Workplan for the Geophysical Prove-Out (GPO) Demonstration. The purpose of the GPO is to demonstrate the effectiveness of the geophysical equipment used to detect ordnance at the facility. GPO field work was conducted from August 9, 2004 through August 27, 2004. The report documenting the results of the GPO was approved in October 2005. From 2005 through 2007, the Facility developed a Conceptual Site Model (CSM) for ordnance. This model incorporated the results of the GPO and evaluated the site ordnance cleanup in light of the results of the GPO. DTSC reviewed the report and provided comments, and an updated CSM incorporating DTSC’s comments was submitted in July 2007. The CSM is a living document, and will be updated as additional ordnance cleanup activities are completed. In August 2007, Aerojet submitted a Workplan for additional ordnance sweeps to address data gaps identified in the Conceptual site model. DTSC reviewed this Workplan in fall 2007, and a revised Workplan was submitted in March 2008. DTSC approved the Workplan in April 2008, and field activities are expected to be completed in the latter part of 2008. Following completion of ordnance sweep activities, Aerojet will prepare a Feasibility Study outlining possible future land uses and any additional cleanup efforts required. DTSC will than review this Feasibility Study and select a proposed future land use. The proposed land use will then be public noticed for public review and comment. Options for cleaning up perchlorate and explosive chemicals in subsurface water will be evaluated based on future land use.
The October 14, 1994 Aerojet-DTSC Corrective Action Administrative Agreement on Consent is a comprehensive 44-page report that details the contamination challenges at the Chino Hills facility.
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