He has served as lead counsel in numerous cases at the appellate level, with representations including arguments before the various federal circuits and the United States Supreme Court. Tom's experience includes matters involving environmental, international, transportation, human health risk, and consumer products issues. He has served as lead counsel on numerous complex litigation and enforcement matters involving private parties, state and federal agencies, and the U.S. Department of Justice and its state counterparts.

On regulatory matters, Tom represents major corporations, trade associations, and commercial and business ventures in the transportation, semiconductor, consumer products, and chemical sectors. He represents them on a variety of compliance, enforcement, and counseling matters involving the Clean Air Act (with a particular focus on Climate Change and mobile sources), the Clean Water Act, the federal aviation statutes, the Safe Drinking Water Act, scientific risk assessments, workplace health issues, international environmental issues, and hazardous materials transportation. He is also the author of a leading deskbook on water regulation.

Tom joined Beveridge & Diamond in 1982 and has served as Chairman of the Litigation group. Prior to joining the firm, he served as a law clerk to the Honorable John J. Sirica of the U.S. District Court for the District of Columbia. He is a member of the bar of the United States Supreme Court and numerous federal trial and appellate courts.