Tom Donnelly has practiced environmental and insurance coverage law for 25 years. He represents clients in environmental litigation, toxic tort, and administrative proceedings; provides environmental compliance counseling and due diligence/transactional support; and assists clients in securing defense and indemnity from their liability insurers. Tom's environmental and insurance coverage clients have included high-tech, aerospace, energy, oil and gas, and metals and mining companies; auto manufacturers; utilities; equipment and consumer product manufacturers; food companies; retailers; financial institutions; and real property owners and developers. He has appeared in all federal district courts in California, the Ninth and Eleventh Circuit Courts of Appeals, and California trial and appellate courts.

Tom's recent representations include: Chevron and Fluor in environmental litigation matters; Lennar, Gruma (food company), and various equipment and consumer product manufacturers in Proposition 65 lawsuits; Firestone Building Products in a regulatory enforcement matter; Nvidia (visual computing), Procter & Gamble, and SanDisk (data storage) in environmental compliance matters; Sutter Home Winery in securing environmental permits for a new winery; various oil and gas companies in climate change compliance matters; and Wells Fargo Bank in environmental due diligence related to real property transactions. For Pacific Gas & Electric Company, after a seven-week trial, Tom secured a verdict that a policy issued by AIG affiliates covered property damage claims (totaling $24 million) asserted against PG&E.

Tom is listed in Chambers USA as one of the leading environmental attorneys in the state of California and has been recognized as a leading environmental attorney by several other trade publications.