Jaimy L. Hamburg

Product Liability & Mass Torts, Infrastructure Investment, Chemicals


Jaimy Hamburg is a litigator and environmental lawyer who represents clients in complex environmental litigation, including toxic tort suits, class actions, citizen suits and government enforcement actions. Jaimy also advises clients on environmental issues in business transactions, such as asset and stock transactions, real estate transactions and financings. She also advises on the investigation and cleanup of contaminated sites. Jaimy was recognized by Legal 500 as a Next Generation Partner three years in a row (2021-2023) and a 2020 Rising Star, which highlights lawyers who make a material difference to the practice. 

Jaimy joined Mayer Brown in 1998, after three years of practicing environmental law with a large law firm in Washington, DC.


  • Toxic tort, product liability, and class actions — Represents clients against individual toxic tort claims, mass claims and class actions in federal and state courts alleging personal injuries and property damages. Cases have included claims involving perfluoroalkyl and polyfluoroalkyl substances, chlorinated solvents, dioxins, PAHs, and heavy metals in connection with drinking water, manufacturing facilities, manufactured gas plants, wood treatment facilities, petroleum refineries, and metals mining sites. Represented clients in product liability cases involving exposure to food flavorings and hydrochloric acid.
  • Citizen suits — Represents clients in suits brought by citizens' groups seeking injunctive relief and damages for alleged violations of environmental laws. Defended natural gas distribution company against claims that historic manufactured gas pipelines leaked contaminants that allegedly coated municipal water mains, presenting an imminent and substantial endangerment to the city’s drinking water supply. Defense included Daubert hearings and two-week hearing on city’s motion for preliminary injunction, which the court denied finding that city was unlikely to succeed on the merits.  City of Evanston v. Northern Illinois Gas Co. (N.D. Ill. 2019).
  • Cost recovery claims — Represents clients pursuing and defending private cost recovery as well as in suits brought by the federal government seeking cost recovery. Represented clients seeking cost recovery under CERCLA and state law from a former property owner, resulting in favorable summary judgment in the case of Spectrum International Holdings, Inc. v. Universal Cooperatives, Inc. (D. Minn. 2006). Represented a primary PRP at a historic metals mining site, including defense of CERCLA cost recovery action by the federal government, assertion of claim for cost reimbursement from the Superfund, and assertion of contractual claim for indemnity from another PRP. 
  • Government enforcement actions — Represents clients against government actions arising out of alleged violations of environmental laws and permits. Represented client in connection with Illinois EPA notices of violation with respect to air permitting. Represented client in an EPA enforcement action under TSCA involving PCBs in natural gas pipeline systems. Defended a petroleum refinery in federal and state multi-media enforcement actions alleging violations of the Clean Air Act, the Clean Water Act, RCRA and state statutes. Defended a client in an enforcement action brought by the Illinois Attorney General regarding an alleged waste disposal site related to the federal government's Operation Silver Shovel corruption probe. 
  • Environmental issues in transactions — Varied practice that includes the evaluation of environmental risks and negotiation of related terms and agreements for clients involved in the purchase and sale of business assets and equity and financing arrangements. Managed environmental due diligence and advised on risk management on behalf of lenders for loan portfolios secured by real property. Represented a REIT in buying and selling real property, including the creation of escrows, environmental insurance and other mechanisms for post-closing environmental due diligence, cost sharing and risk management. Conducted environmental due diligence on behalf of an investment bank for employee buy-out of a number of paper and paperboard manufacturing facilities. 
  • Environmental investigations and cleanups — Advises clients on conducting environmental investigations and cleanups pursuant to federal and state law, including voluntary cleanup programs in Illinois and Minnesota.
  • NEPA — Represented clients in NEPA action against federal agency in connection with large international transportation infrastructure project in Detroit area.


  • Washington University, BA, college honors
  • University of Pennsylvania Law School, JD, magna cum laude
    Comments Editor, University of Pennsylvania Law Review, Order of the Coif


  • Illinois
  • Minnesota
  • District of Columbia


  • US District Court for the Northern District of Illinois