Munitions and chemicals of concern from the former Aerojet Ordnance Co. in Chino Hills will be investigated and remediated on approximately 20 acres of the 800-acre site located at the end of Woodview Road, south of Peyton Drive, adjacent to the Vellano Country Club development.
Officials from the Department of Toxic Substances Control (DTSC), joined Tuesday’s city council meeting remotely to provide an overview of Aerojet and how the next phase of cleanup will be handled.
Department officials announced that two documents are available for public review: a “Statement of Basis” and the “CEQA Initial Study.”
Residents have until Thursday, Nov. 11 to review the documents and provide comments under a 30-day period that began Wednesday, Oct. 13.
The documents can be found by visiting envirostor.dtsc.ca.gov. Enter “Chino Hills Aerojet” in the search bar and click on the second Aerojet description in the dropdown menu. Click on the “community involvement” tab to read the documents.
For those who wish to read a hard copy, a large white binder containing the documents as well as the “Human and Ecological Risk Assessment” is available at the Chino Hills Branch Library, 14020 City Center Drive.
The DTSC will conduct a community meeting using Zoom on Thursday, Oct. 28. The time and details will be published in next week’s edition of the Champion.
The DTSC has been providing oversight of the cleanup of Aerojet since 1997.
Aerojet is hoping to eventually build residential units on the property which is zoned rural residential.
Of the 800 acres, Aerojet owns 580 acres and the remaining acres were used as “buffer” land.
Aerojet manufactured and tested explosives and chemical warfare agents from 1954 to 1995.
Potential hazardous substances released into the soil and or surface or subsurface water included perchlorate, explosives known as HMX and RDX, 1,3,5-trinitrobenzene, tear gas, lead, dioxin, and munitions and chemicals of concern (known as MEC), some of which used depleted uranium.
The Champion asked the DTSC for a cost estimate on the amount charged to Aerojet for its oversight activities since 1997.
According to DTSC spokesman Russ Edmondson, DTSC records going back to 2007 show a total of $1,179,553.
According to the Statement of Basis, soil potentially containing MEC will be removed in portions of “management area 1.”
Excavation will use common earthmoving equipment such as scrapers, water trucks, excavators, bulldozers, and dump trucks to remove materials estimated from 1 to 4 feet deep, exposing undisturbed native bedrock.
Controls such as sediment traps, sandbags, straw bale barriers and hydroseeding would be placed in and around the disturbed areas to minimize potential movement of eroded sediment.
Excavated soil would remain at the facility and be transported to an on-site holding area.
Explosive Ordnance Disposal staff will observe the disturbed areas for MEC and ensure that construction personnel follow safety precautions.
Explosive Ordnance Disposal staff will also conduct ordnance sweeps.
Recovered MEC items will be managed and treated following methods and protocols that were previously implemented in the project area.
MEC determined to be safe for transport will be secured in bunkers at the facility pending disposition. When sufficient quantities of stored MEC are reached, the materials will be evaluated for offsite management or destroyed at the facility using contained detonations.
During previous MEC removal, recovered items were destroyed by placing them in shallow pits surrounded by donor explosives, then covering the pits with soil and detonating the explosives.
The City of Chino Hills asked for a health and ecological risk assessment after residents expressed concerns during a community meeting in 2016.
The assessment work plan was approved by the DTSC in October 2018.
The report, dated Feb. 28, 2020, shows a total incremental cancer risk and total hazard indices “below the de minimis level of 1E-06 and the threshold level of 1, respectively,” indicating that “unrestricted use of the facility is acceptable.”
Opened in 1954
Aerojet began operating in 1954 as an ordnance-testing facility.
In 1974, the facility became involved in research, development, assembly, and testing of 25- and 30mm high-explosive incendiary projectiles, armor-piercing incendiary projectiles composed in part of depleted uranium, and fuzes, primarily the M505 fuzes.
Ordnance testing activities were undertaken in specific areas on the property, primarily the box canyons in the central portion of the site.
DTSC has approved reports documenting cleanup and corrective measures from 2006 to 2010.
More than 3,000 tons of soil containing depleted uranium in 19 areas were removed under the oversight of the Radiologic Health Branch of the Department of Health Services, according to Champion archives.
Depleted uranium projectiles, able to pierce armor, were fired into target plates and sand to test performance.
The DTSC concluded in a 2004 report that depleted uranium levels in the soil, surface water and groundwater were within acceptable levels.
More than 47,000 M505 fuzes and 120,000 pounds of inert ordnance fragments were recovered from the eastern portion of the facility called the “open burn/open detonation” unit which was the most heavily impacted area of Aerojet.
Aerojet has conducted surface and subsurface water samplings to monitor the levels of perchlorate, uranium, and explosives. The DTSC approved sampling reports submitted in 2005, 2006, 2007, and again in 2017, 2018, and 2019.
Cancer assessments were performed in 1999 by Loma Linda University Medical Center’s Cancer Institute after residents expressed concerns.
The study reported no excesses or increases in the numbers of cancers.
Some residents filed a lawsuit against Aerojet where individuals received settlements in the early 2000s.