Surface and groundwater samplings taken on the former Aerojet munitions plant in Chino Hills required by the California Department of Toxic Substances Control showed no health risks, according to test results presented by Aerojet.
Aerojet manufactured and tested explosives and chemical warfare agents from 1954 to 1995 at the end of Woodview Road, south of Peyton Drive, under government contracts.
Under the supervision of the Department, Aerojet has been cleaning the site since 1995 to a level that would allow residential development.
In the 1960s and 1970s, Aerojet conducted research and development of munitions involving chemicals related to mustard gas as well as organic compounds originally developed as nerve gas.
The additional water samples were requested after residents raised concerns at a public meeting at the Chino Hills Community Center in 2016.
The Department was preparing to decide on the cleanup for munitions and explosives of concern when residents instead raised questions about potential chemical contamination in the soil, surface water, and groundwater.
As a result of the comments, the City of Chino Hills asked the Department to require Aerojet to sample the water and conduct a “health and ecological risk assessment.”
The munitions clean-up project, located in two relatively small areas of the site, did not proceed.
Scott Goulart, senior director for environmental remediation for Aerojet, said the surface water samples required by the Department were collected in January of this year and the results indicated no health risks posed by chemicals of concern.
He said the results were comparable to the results from samples taken in the mid-2000s.
Mr. Goulart said the subsurface water samples required by the Department were collected in May 2018 and under current site conditions, results indicate no health risks posed by chemicals of concern.
Those results were also comparable to those taken in the mid-2000s, he said.
The City of Chino Hills also asked that samples be taken of wells on an adjacent property occupied by the family-owned HHH Ranch.
The Department sampled the ranch’s wells in March of this year and found them to be below California and U.S. EPA maximum contaminant levels for drinking water, according to community development director Joann Lombardo.
Since the 2016 meeting, Aerojet has been working with The Department on how the health and ecological risk assessment should be conducted.
Mr. Goulart said Aerojet submitted a draft workplan in February of this year, and the Department provided comments June 4.
Aerojet responded to the comments and will submit a revised workplan this week, Mr. Goulart said.
Once the Department approves the work plan, Aerojet will undertake the assessment, he said.
Documents related to Aerojet are available at www.envirostor.dtsc.ca.gov/public/ and enter Chino Hills. At the dropdown menu, select “Aerojet Chino Hills Facility” and click on the view information link.