Cleanup staff

Santa Susana: A Comprehensive Cleanup

Cleanup Process

The Santa Susana Field Laboratory was historically used to test rocket engines for NASA and the military, and to perform non-military nuclear energy research at Department of Energy’s (DOE) Energy Technology Engineering Center (ETEC) for leading-edge nuclear power, solar and energy-efficiency technology development.

After more than 50 years of operation, nuclear research ended in 1988 and rocket engine testing ceased in 2006. These past operations left residual chemical and radiological contamination in some areas of the site, in soil and groundwater.

Santa Susana is divided into four administrative areas that reflect its past operations, current ownership and cleanup responsibility. Boeing owns most of the property; the U.S. government owns a portion, administered by NASA and the U.S. Department of Energy leased a portion of land from Boeing’s predecessor.

In 2007, all three parties signed a comprehensive cleanup agreement with the California Department of Toxic Substances Control (DTSC). Under this Consent Order, Boeing committed to performing a risk-based cleanup of soil and groundwater contaminated by chemicals, applying standards that are in-line with other cleanup sites throughout California.

In 2022, the California Environmental Protection Agency (CalEPA) announced a comprehensive framework that establishes strict cleanup protocols and timelines for Boeing. The framework involves two state agencies — the DTSC and the Regional Board — and accelerates cleanup, reduces the potential for technical disputes and establishes a process to resolve them quickly, avoiding delays from litigation. The comprehensive framework agreement also includes safeguards to protect important environmental and cultural resources at the site, does not impact the validity of the conservation easement recorded on Boeing’s property, and includes an expedited cleanup process to streamline and accelerate cleanup of contamination at Santa Susana.

Area IV of Santa Susana has localized areas with radioactive contamination above naturally-occurring levels, which is the responsibility of the Department of Energy. In 2012, the U.S. Environmental Protection Agency completed an extensive radiation survey and found that low levels of residual contamination from past nuclear energy research affects approximately 40 acres of this portion of the site. The results demonstrate that previous

Also, numerous studies conclude that there is no evidence that past operations at the Santa Susana Field Laboratory have affected the health of the local community.

Making Progress

Efforts to remove contamination from the site began three decades ago and Boeing’s final soil cleanup could begin as early as 2026, in accordance with our cleanup agreement framework with the California Environmental Protection Agency. Through environmental studies and interim cleanup measures, Boeing has:

  • Removed or treated nearly 45,000 cubic yards of soil, which is enough to fill more than 2,800 dump trucks
  • Demolished 300 structures, in accordance with state and federal standards
  • Analyzed 38,000+ soil, bedrock and groundwater samples
  • Drilled 260 groundwater monitoring and extraction wells
  • Installed a state-of-the-art groundwater extraction treatment system
  • Built two advanced stormwater treatment systems to meet water quality standards
  • Created two biofiltration systems to naturally treat stormwater
  • Restored 900 acres of land

In addition, more than 300 structures have been decommissioned and demolished in accordance with state and federal standards.

Boeing has received commendations from the California Stormwater Quality Association and the Wildlife Habitat Council for its cleanup and restoration efforts. We will continue to work with a variety of educational and environmental organizations on research to promote new and innovative approaches to cleanup, remediation and restoration, along with enhancing knowledge of Santa Susana's ecology.

Visit the DTSC website for more cleanup news and information, including technical reports.

Cleanup staff Boeing has staff onsite who are dedicated to investigation and cleanup activities with oversight from the Department of Toxic Substances Control.

Soil Cleanup

Soil cleanup equipment Boeing has begun to address soil contamination by removing or treating 45,000 cubic yards of soil, which is enough to fill more than 2,800 dump trucks.

Boeing has conducted interim cleanup measures at Santa Susana while building the scientific basis for cleanup pending final regulatory approval. Boeing has removed or treated 45,000 cubic yards of soil; analyzed 38,000 soil and groundwater samples; drilled 260 groundwater monitoring and extraction wells; and dismantled more than 300 structures.

In 2007, Boeing, NASA and the DOE signed a comprehensive cleanup agreement with the DTSC. Boeing is committed to completing a cleanup of the Santa Susana Field Laboratory that is fully protective of both human health and the environment, consistent with the field lab’s future as open space habitat.

In 2022, Boeing agreed to a comprehensive framework developed with the California Environmental Protection Agency (Cal EPA) that establishes strict cleanup protocols and timelines for Boeing. The cleanup framework involves two state agencies —DTSC and the Regional Board — and provides Boeing with a clear process, schedule and criteria for future decision-making, while protecting important biological and cultural resources.

Federal and state laws require sites to be cleaned up to limit human health and environmental risks based upon future land use. Boeing has agreed not to contest DTSC’s selection of a broad range of cleanup standards, including a resident with garden exposure standard. Under that standard, soil would be remediated to allow people to live on-site and consume produce from a backyard garden, even though the site will be preserved as open space. Under the terms of the agreement, our final soil and groundwater cleanup is slated to start as soon as 2026.

Groundwater Cleanup

With oversight from the DTSC, Boeing is conducting an investigation of groundwater under and near the Santa Susana site. The goals of the program are to characterize the nature and extent of chemical contamination, evaluate potential risks to people and the environment, and gather data to support the DTSC site-wide cleanup plan.

The investigation entails analyzing groundwater from 260 on- and off-site wells, mapping the geology of Simi Hills, and identifying and sampling seeps and springs. An extraction treatment system treats groundwater pumped from wells throughout the site. The system is capable of treating approximately 100 gallons of water per minute and removes chemicals like trichloroethylene (TCE) and 1,2-dichloroethylene (1,2-DCE).

Under the direction of the Groundwater Advisory Panel, several new techniques have been developed and employed at Santa Susana to provide a detailed examination of the fractured bedrock and deep groundwater. This includes analyzing more than 8,400 rock samples for chemicals, as well as installing measuring devices in numerous wells to study the distribution of the chemical contamination.

There is only one location, in the northeast area of the site, where off-site groundwater appears to be affected. A comprehensive evaluation of the property surrounding the Santa Susana site reveals no traces of chemicals in groundwater emerging above-ground through seeps and springs.

Boeing is conducting a year-long study of possible groundwater cleanup methods using in-situ chemical oxidation. This technology involves injection of a potassium permanganate solution into contaminated groundwater at the northeast corner of the site.

Cleanup staff A team installs groundwater monitoring wells as part of Boeing’s seeps and springs investigation.

Stormwater Management

Cleanup staff Boeing designed and constructed two advanced treatment systems to improve stormwater quality at Santa Susana.

Stormwater at Santa Susana is regulated under a permit issued by the Los Angeles Regional Water Quality Control Board (Regional Board).

Stormwater follows the natural topography through a series of channels and ponds until it leaves the Santa Susana site. Certain points along these natural pathways, called “outfalls,” are selected by the Regional Board as locations where monitoring and sampling should be performed to measure water quality.

Twelve outfalls at Santa Susana are monitored under the guidelines of a National Pollutant Discharge Elimination System permit. Boeing collects stormwater samples to be analyzed for a variety of pollutants when water flow is observed in the outfalls.

Over the past 12 years, Boeing has spent more than $100 million on numerous stormwater management and treatment systems to protect surface water quality and meet permit limits. We have maintained over 99% compliance with the strict permit limits which are in many cases, lower than what is required for the water that people drink. The permit exceedances that have occurred are generally associated with metals and inorganics at naturally-occurring levels, or constituents commonly found in surface water following regional wildfires.

In an effort to meet these limits, Boeing has instituted a rigorous monitoring program and is making progress improving the quality of stormwater runoff that leaves the site by:

  • Working with the Stormwater Expert Panel, an independent team of five internationally recognized experts who provide recommendations on how to best meet compliance objectives, at the direction of the Regional Board.
  • Designing and constructing two state-of-the-art storm water treatment systems that use processes and chemicals similar to those used by city and county municipalities to make clean drinking water;
  • Removing more than 25,000 cubic yards of soil that may have been adversely affecting stormwater runoff;
  • Installing a biofilter based on a recommendation from the Stormwater Expert Panel in collaboration with the Los Angeles Conservation Corps, Pollinator Partnership and the Wildlife Habitat Council that was recognized by the California Stormwater Quality Association as a creative solution for improving stormwater in California.
  • Completing a Human Health Risk Assessment (HHRA) that evaluated potential exposure of individuals who may come into contact with stormwater from the Santa Susana Field Lab in drainage areas immediately downstream of the property boundary while hiking, rafting or other recreational uses. The HHRA was reviewed and approved by the California Office of Environmental Health Hazard Assessment (OEHHA) and concluded that:
    • Potential recreational exposures to Constituents of Potential Concern (COPCs) in surface water runoff exiting the Santa Susana site via Outfalls 001, 002, 008, 009, 011, 018, and 019 are below levels of concern as established by Cal-EPA and USEPA. This includes those COPCs that have had NPDES permit limit exceedances, such as lead and dioxins.
    • Both the Regional Board and the California Office of Environmental Health Hazard Assessment (OEHHA) agreed with this conclusion. Every year, the independent stormwater expert panel reviews stormwater monitoring data. These annual reviews continue to show that the human health risk assessment findings have not changed.