The Department of Toxic Substances Control (DTSC), pursuant to Section 25143 of the Health and Safety Code and Section 66260.210 of the California Code of Regulations Title 22, has issued a variance to Santa Maria Regional Landfill (CAH111000114) to receive and dispose of treated wood waste from generators, authorized transporters, and/or authorized handler facilities at Santa Maria Regional Landfill (active area lined landfill cell). 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-00179, Santa Maria Regional Landfill will ensure the treated wood waste will be appropriately managed. Because the variance activities are consistent with operations of a previously approved project, DTSC has prepared an addendum to a previously certified environmental impact report consistent with Public Resources Code 21166 and Title 14 CCR 15162-15164. The variance will expire on September 14, 2021 with possibility of extension for an additional six months.