The Department of Toxic Substances Control (DTSC) has issued a variance to San Francisco Municipal Agency (SFMTA) (CAD9820008732) to generate and accumulate treated wood waste on-site. The treated wood waste is generated as a result of the railway replacement. 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-LG-00326, San Francisco Municipal Agency (SFMTA) will ensure the treated wood waste will be appropriately managed. The treated wood waste management activities include replacing the old tie-ballast railway with a direct fixation fastening system over concrete slab. As such, the old wood ties would need to be disposed. 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. San Francisco Municipal Agency (SFMTA) is a transit agency, who runs light rail vehicles on railway. Under the variance, the authorized large quantity generator may generate and accumulate treated wood waste on-site. Accumulation of treated wood waste includes taking appropriate precautions to prevent unauthorized access to and prevent leaching to the environment of the treated wood waste. No transportation activities are authorized as a part of this variance. The variance will expire on October 27, 2021 with possibility of extension for an additional six months.