The Department of Toxic Substances Control (DTSC) has issued a variance to Keller Canyon Landfill Company (CAL000094199) to receive and dispose of treated wood waste from generators, transporters, and/or handler facilities. Operations related to treated wood waste will be consistent with previous treated wood waste activities conducted by the applicant. The variance allows treated wood waste to be managed under procedures different from, but equally protective to human health and the environment to, the provisions of California Health and Safety Code (HSC) Articles 6, 6.5 and 9 of Chapter 6.5 and California Code of Regulations (CCR), Title 22, Division 4.5, Chapters 12, 13, 14, 15, 16, 18, and/or 20. Under the terms and conditions of Variance TWW-2021-DF-00049, Keller Canyon Landfill Company will ensure the treated wood waste will be appropriately managed. Background: Treated wood waste is a fully regulated California-only hazardous waste because it exhibits the hazardous waste characteristic of toxicity. From 2007 to December 31, 2020, treated wood waste was managed under alternative management standards, established in 22 CCR 67386. The legislation that authorized the alternative management standards for treated wood waste expired on December 31, 2020. Without the issuance of the variance, Keller Canyon Landfill Company would be required to seek a permit as a hazardous waste disposal facility. Keller Canyon Landfill Company is a solid waste management company. The applicant previously conducted treated wood waste management activities under the now expired alternative management standards established at 22 CCR 67386. Project Activities: Under the variance, the Facility will accept treated wood waste from generators, and authorized handlers and/or transporters for disposal, however it will be managed as a California hazardous waste, under authority of HSC 25200 et seq.. Operations generally include unloading and disposal of treated wood waste within Keller Canyon Landfill, which has aprepared subgrade, 12-inch underdrain granular drainage layer, non-woven geotextile filter, 24-inch thick low permeability soil layer with maximum permeability of 1x10-7 cm/sec or less, 80-mil high density polyethylene (HDPE) liner, (double sided textured), non-woven geotextile, cushion layer, 12-inch LCRS granular drainage layer, non-woven geotextile filter, and 12-inch thick operations (protective cover soil) layer. Acceptance and disposal of TWW will be consistent with hazardous waste management and disposal standards specified in the variance. The variance will expire on August 29, 2021 with possibility of extension for an additional six months.