Gabe Cisneros, an Associate Principal and Senior Geologist, recently presented the new MTCA Silica Gel Cleanup guidance as part of a Law Seminars International (LSI) MTCA seminar. In late November 2023 the Washington State Department of Ecology released a revised guidance for silica gel cleanup (SGC). Gabe, who has extensive experience with MTCA in the context of upland soil, groundwater, and soil vapor, presented an overview of this updated SGC. 

Gabe’s presentation covered various aspects of SGC, including distinctions between non-polar hydrocarbons and polar non-hydrocarbon, the difference between fresh diesel and weathered diesel, how SGS works, and the reasons behind its controversial nature. Additionally, Gabe discussed when to use SGC and used anonymous examples from his projects to show how it can be useful. 

Gabe’s presentation aimed to provide valuable insights into the latest developments and guidelines related to the Silica Gel cleanup under the MTCA guidance.