Chiquita Canyon Landfill Imminent and Substantial Endangerment Determination and Order
Summary
SCH Number
2025040190
Public Agency
California Department of Toxic Substances Control
(DTSC)
Document Title
Chiquita Canyon Landfill Imminent and Substantial Endangerment Determination and Order
Document Type
NOE - Notice of Exemption
Received
Posted
4/3/2025
Document Description
The Department of Toxic Substances Control (DTSC) issued an Imminent and Substantial Endangerment Determination and Order (Order) to the owners and operators of Chiquita Canyon Landfill (CCL), Chiquita Canyon, LLC, Chiquita Canyon, Inc., and Waste Connections US, Inc., to undertake certain removal actions which the Department of Toxic Substances Control (DTSC) has identified as necessary to address threatened releases of hazardous substances. Due to conditions created by a Subsurface Elevated Temperature (SET) event at CCL, there is a threat of release of hazardous substances, including benzene and methyl ethyl ketone (MEK), contained in the leachate generated by the landfill waste mass. The Order (Docket No. HSA-FY24/25-082) will require specific actions and the preparation and implementation of Removal Action Workplans for the protection of public health and the environment.
Background: CCL is approximately 639 acres in size and is permitted as a class III non-hazardous municipal solid waste landfill. The area surrounding CCL consists of industrial, agricultural, and residential properties. The nearest residential development is the Val Verde community, located approximately 1,000 feet northwest of CCL. CCL was first approved for waste disposal in 1967 and had been in use as a class III non-hazardous solid waste landfill since 1972. CCL reports that it ceased accepting waste as of January 1, 2025. On or about May 2022, an uncontrolled SET event significantly expanded in the inactive north-western portion of CCL in an area about 30 acres in size, in portions of the landfill identified as Cell 1/2A, Module 2B/3, Module 4, and Module 2B/3/4 P2. As a result of this uncontrolled SET event, various regulatory agencies, including DTSC, are actively involved with overseeing CCL as part of a Multi-Agency Critical Action Team (MCAT). The MCAT also includes agencies such as the United States Environmental Protection Agency (USEPA); California Environmental Protection Agency (CalEPA); South Coast Air Quality Management District (South Coast AQMD); Department of Resources Recycling and Recovery (CalRecycle); Los Angeles Regional Water Quality Control Board (RWQCB); California Air Resources Board (CARB); California Office of Environmental Health Hazard Assessment (OEHHA); Los Angeles County Departments of Public Health, Regional Planning, and Public Works; and the Los Angeles Certified Unified Program Agency. More recent information provided by CCL in January and February 2025 indicates that the SET event is further expanding to the east and south of the existing geomembrane cover and has reached an area which includes storage tanks containing hazardous leachate (“Tank Farm 9”), and now encompasses approximately 90 acres of CCL. Recent data also confirm that settlement is occurring around Tank Farm 9, and that locations proximate to Tank Farm 9 have developed significant fissures and tension cracks, as well as a sinkhole. Among other reasons detailed in the Order, the current conditions at CCL present a serious threat to public health, welfare, and the environment, and an emergency requiring removal actions to abate, because: 1. The storage tanks containing hazardous leachate located in Tank Farm 9 could be compromised by the expanding SET event, leading to destabilization and loss of integrity of the tanks, and subsequent releases into the environment, which could migrate to soils, and into surface and groundwater; 2. The rapidly deteriorating conditions in areas of the SET event’s expansion (e.g., increasing presence of high temperature and high pressure leachate and gases, and worsening ground settlement) present growing safety hazards which may jeopardize the continued ability to undertake removal actions at CCL (e.g., could prevent moving State of California – California Environmental Protection Agency Department of Toxic Substances Control the storage tanks) once risks to personnel who would perform the removal actions become unacceptably high due to the increasing potential for unexpected releases of hot and pressurized leachate and gases, worsening ground settlement creating underground voids or sinkholes (risk to personnel, and risk that could result in leachate tank cracking), and other physical hazards; 3. There are currently no natural or installed barriers which could serve to prevent or limit the expansion of the SET event throughout the entire landfill; and, 4. The elevated temperatures and chemicals produced by the SET event threaten the integrity of the landfill liner, which protects the two aquifers in the vicinity of CCL from intrusion of hazardous leachate, and thus protects the groundwater supplies. Project Activities: The Order requires the owners and operators of CCL to undertake, and prepare Removal Action Workplans in connection with, three removal actions: 1. Install a geomembrane over areas of the CCL site where a cover currently does not exist, and to where the SET event has expanded or has the potential to expand; 2. Temporarily relocate and stabilize storage tanks containing hazardous waste leachate which are located in an area of CCL which could be compromised by deteriorating conditions caused by the SET event; and, 3. Install a barrier to protect critical landfill infrastructure (Cell 8A) from intrusion by the SET event. These removal actions will abate the imminent and substantial endangerment by preventing infiltration of oxygen and water into the landfill waste in areas of the reaction’s expansion to control gas emissions and associated odors; preventing threatened releases from destabilization of leachate storage tanks located in areas showing signs of elevated temperatures, settlement, and differential movement; and, curtailing lateral expansion of the reaction into critical landfill infrastructure
Contact Information
Name
Pete Ruttan
Agency Name
Department of Toxic Substances Control
Job Title
Project Manager
Contact Types
Lead/Public Agency
Phone
Email
Location
Coordinates
Counties
Los Angeles
Regions
Southern California
Zip
91384
Other Location Info
29201 Henry Mayo Drive, Castaic, California 91384
Notice of Exemption
Exempt Status
Emergency Project
Type, Section or Code
Sec. 21080(b)(4); 15269(b)(c)
Reasons for Exemption
This Project consists of response actions necessary to prevent or mitigate an emergency, determined by DTSC to be “an imminent or substantial endangerment to the public health or welfare or to the environment, because of a release or a threatened release of a hazardous substance .…” (Health and Safety Code section 78870(a)).
CCL is close to several residential communities, and some homes are as close as 1,000 feet to the reaction area. The conditions created by the uncontrolled SET event threaten further releases of hazardous substances such as benzene due to the increasing volumes of leachate produced by the reaction, as well as the deteriorating site conditions caused by the elevated temperatures and chemical reactions.
In light of the above, and for the more extensive reasons and facts contained in the Imminent and Substantial Endangerment Determination and Order and in the documents that constitute the administrative record supporting that Order, DTSC has determined that an emergency imminent and substantial endangerment to public health and the environment exists, and that this removal action is exempt under the emergency provisions of the California Environmental Quality Act.
Further, and as an independent basis for exemption, the removal action work is necessary to avoid or abate a present and substantial adverse environmental endangerment – i.e., will not cause a substantial or potentially substantial adverse change in the environment, but rather will help abate such changes. Based on the above reasons and Order record, DTSC has determined with certainty that there is no possibility that the Project activities may have a significant effect on the environment because the project would not result in “a substantial, or potentially substantial, adverse change in any of the physical conditions within the area affected by the project, including land, air, water, minerals, flora, fauna, ambient noise, and objects of historic or aesthetic significance” so therefore qualifies for the common sense exemption.
Exempt Status
Categorical Exemption
Type, Section or Code
Enforcement Actions by Regulatory Agencies (14 CCR, Sec. 15321(a))
Reasons for Exemption
This Project consists of response actions necessary to prevent or mitigate an emergency, determined by DTSC to be “an imminent or substantial endangerment to the public health or welfare or to the environment, because of a release or a threatened release of a hazardous substance .…” (Health and Safety Code section 78870(a)).
CCL is close to several residential communities, and some homes are as close as 1,000 feet to the reaction area. The conditions created by the uncontrolled SET event threaten further releases of hazardous substances such as benzene due to the increasing volumes of leachate produced by the reaction, as well as the deteriorating site conditions caused by the elevated temperatures and chemical reactions.
In light of the above, and for the more extensive reasons and facts contained in the Imminent and Substantial Endangerment Determination and Order and in the documents that constitute the administrative record supporting that Order, DTSC has determined that an emergency imminent and substantial endangerment to public health and the environment exists, and that this removal action is exempt under the emergency provisions of the California Environmental Quality Act.
Further, and as an independent basis for exemption, the removal action work is necessary to avoid or abate a present and substantial adverse environmental endangerment – i.e., will not cause a substantial or potentially substantial adverse change in the environment, but rather will help abate such changes. Based on the above reasons and Order record, DTSC has determined with certainty that there is no possibility that the Project activities may have a significant effect on the environment because the project would not result in “a substantial, or potentially substantial, adverse change in any of the physical conditions within the area affected by the project, including land, air, water, minerals, flora, fauna, ambient noise, and objects of historic or aesthetic significance” so therefore qualifies for the common sense exemption.
Exempt Status
Other
Type, Section or Code
Common Sense Exemption (14 CCR, Sec. 15061(b)(3))
Reasons for Exemption
This Project consists of response actions necessary to prevent or mitigate an emergency, determined by DTSC to be “an imminent or substantial endangerment to the public health or welfare or to the environment, because of a release or a threatened release of a hazardous substance .…” (Health and Safety Code section 78870(a)).
CCL is close to several residential communities, and some homes are as close as 1,000 feet to the reaction area. The conditions created by the uncontrolled SET event threaten further releases of hazardous substances such as benzene due to the increasing volumes of leachate produced by the reaction, as well as the deteriorating site conditions caused by the elevated temperatures and chemical reactions.
In light of the above, and for the more extensive reasons and facts contained in the Imminent and Substantial Endangerment Determination and Order and in the documents that constitute the administrative record supporting that Order, DTSC has determined that an emergency imminent and substantial endangerment to public health and the environment exists, and that this removal action is exempt under the emergency provisions of the California Environmental Quality Act.
Further, and as an independent basis for exemption, the removal action work is necessary to avoid or abate a present and substantial adverse environmental endangerment – i.e., will not cause a substantial or potentially substantial adverse change in the environment, but rather will help abate such changes. Based on the above reasons and Order record, DTSC has determined with certainty that there is no possibility that the Project activities may have a significant effect on the environment because the project would not result in “a substantial, or potentially substantial, adverse change in any of the physical conditions within the area affected by the project, including land, air, water, minerals, flora, fauna, ambient noise, and objects of historic or aesthetic significance” so therefore qualifies for the common sense exemption.
Attachments
Notice of Exemption
Disclaimer: The Governor’s Office of Land Use and Climate Innovation (LCI) accepts no responsibility for the content or accessibility of these documents. To obtain an attachment in a different format, please contact the lead agency at the contact information listed above. For more information, please visit LCI’s Accessibility Site.