Sarah A. Slack


Sarah Slack is an environmental lawyer dividing her time between project development and redevelopment work, environmental compliance counseling, transactions, and environmental litigation. She is a partner in the firm’s Business Law Department and a member of the Environmental Regulation Practice Group. Sarah is also an active member in the firm’s Energy Sector where she acts as the subsector lead for our Energy Transition Team. Sarah has extensive experience counseling developer, investor, and lender clients in all aspects of renewable energy project development, including solar, wind, and battery storage projects. Sarah regularly counsels clients on matters related to environmental, social, and governance (ESG), including green claims and greenwashing considerations. In addition, Sarah assists clients with development, financing, and permitting considerations related to carbon capture and hydrogen projects, as well as on matters related to microgrids and EV Infrastructure development, as well as cleantech.

Sarah counsels clients across a variety of industry sectors, from traditional energy and infrastructure matters to renewable energy projects, and from chemical producers to manufacturing companies. She has been involved in numerous development and redevelopment projects and has assisted with obtaining, renewing, and revising construction and operation permits, including permits related to federal and state wetlands, wastewater discharges, air emissions, and special status species.

Sarah has extensive experience counseling clients on the cutting edge of Clean Air Act, Clean Water Act, Superfund, FIFRA, TSCA, and RCRA enforcement, as well as citizen suit litigation, settlement strategies, and related cost recovery, insurance coverage, and indemnity disputes. She also provides counsel to clients regarding air emissions, waste management, underground storage tank compliance, and water discharge permitting and compliance, as well as a variety of compliance matters related to chemicals and chemical usage, including under California’s Proposition 65.

Awards and Recognition

  • Listed in Chambers USA: America’s Leading Lawyers for Business in the fields of natural resources and environmental law (2022-2023)
  • Named to Wisconsin Super Lawyers – Rising Stars® lists (2013-2015)


  • Chair Elect of the Environmental Law Section of the State Bar of Wisconsin

Presentations and Publications

  • Co-author, “Navigating to Net Zero: Regulatory Regimes and Market Trends Impacting Decisions,” Natural Resources & Environment (Summer 2023)
  • Co-author, “Crossing the Line: Navigating Multinational Corporation Chemical Compliance,” Natural Resources & Environment (Fall 2020)
  • Co-author, “Paris or No Paris, Auto Emissions May Fall,” Daily Journal (June 22, 2017)
  • Author, “When is a Pesticide Not a Pollutant? Never: An Analysis of the EPA’s Misguided Guidance,” 90 Iowa L. Rev. 1241 (2005)
09 February 2024 In the News

Sarah Slack Quoted on Environmental Legal Trends for 2024

Foley & Lardner LLP partner Sarah Slack is quoted in the Wisconsin Lawyer article, “Wisconsin Legal Trends 2024,” offering insight on environmental legal trends.
05 December 2023 Article

Proposed Amendments to the Proposition 65 Regulatory Landscape – Changes to Clear and Reasonable Warnings and Safe Harbor Methods under Article 6

Last month, the California OEHHA issued a Notice of Proposed Rulemaking and Announcement of Public Hearing concerning proposed changes to existing sections of the safe harbor warning regulations for consumer products exposures.
21 September 2023 Deals and Wins

Foley Advises Knowles Corporation in Acquisition of Cornell Dubilier

Foley & Lardner LLP served as legal adviser to Knowles Corporation, a leading global supplier of high performance components and solutions, including ceramic capacitors and radio frequency filters, advanced medtech microphones, balanced armature speakers, and audio solutions, in entering a definitive agreement to acquire Cornell Dubilier.
01 June 2023 Press Releases

Foley Earns Top Rankings in Chambers USA 2023

Foley & Lardner LLP is pleased to announce that it has again been recognized by Chambers & Partners as one of the top law firms in the country in the 2023 edition of Chambers USA, America’s Leading Lawyers for Business.
31 May 2023 Article

Wetlands No More? U.S. Supreme Court Limits Federal Regulation of Wetlands in Sackett v. EPA Decision

On May 25, 2023, the Supreme Court issued a decision in Sackett v. EPA, effectively narrowing the scope of federally protected wetlands to which the Clean Water Act applies.
22 March 2023 Deals and Wins

Foley Serves as Legal Adviser to KeyBank in $225M Financing of Scale Microgrids’ Energy Transition Debt Facility

Foley & Lardner LLP advised KeyBank National Association, in its capacity as Administrative Agent and a lender, as well as KeyBanc Capital Markets and City National Bank, as joint lead arrangers, on a loan to Scale Microgrids for a $225 million first-of-its-kind non-recourse project finance debt facility.