Thomas is a recognized technical authority in the characterization and remediation of non-aqueous phase liquids (NAPL), with deep expertise in both light and dense NAPL (LNAPL and DNAPL) across petroleum, chlorinated solvent, and industrial contaminant settings. His areas of expertise include natural source zone depletion (NSZD), monitored natural attenuation (MNA), sorptive reactive media, in situ chemical oxidation (ISCO), aeration-based remediation technologies such as air/bio sparging, soil vapor extraction (SVE), multiphase extraction (MPE), and more recently, the application of advanced data analytics and remote subsurface sensors to support long-term site management. He is particularly focused on optimizing and transitioning active remediation systems to more sustainable, cost-effective passive approaches.

He has led high-resolution conceptual site model development and remedy optimization efforts at sites across the United States, Canada, and internationally, working closely with clients, regulators, and technical teams to implement practical, state-of-the-practice solutions. He has served as lead author and co-author for guidance documents published by Springer Nature, the Interstate Technology and Regulatory Council (ITRC), the American Petroleum Institute (API), the U.S. Department of Defense, and the Cooperative Centre for Contamination Assessment and Remediation of the Environment (CRC CARE) in Australia. He was a trainer for the U.S. Navy technical seminar series, the ITRC internet-based training series on LNAPL site management, and has presented at national and international technical conferences.