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)
11 April 2024 Deals and Wins

Foley Represents ARCHIMED in Acquisition of Majority Stake in Innovative Skincare Company Cellese

Foley & Lardner LLP represented global private equity health care specialist ARCHIMED in its acquisition of a majority stake in Cellese, a developer of innovative topical dermo cosmetics sold under the AnteAGE brand name.
26 March 2024 Deals and Wins

Foley Advises Silicon Valley Bank on Renewable Energy Investment

Foley & Lardner LLP served as legal advisor to Silicon Valley Bank in its capacity as Administrative Agent, Collateral Agent, Sole Bookrunner, Coordinating Lead Arranger, and lender with respect to the financing for the Eldorado Project.
08 March 2024 Article

SEC’s Slimmed Down Climate-Related Disclosures Finally Adopted

On March 6, 2024, the Securities and Exchange Commission adopted regulations that will require public companies to file mandatory climate-related disclosures with the SEC beginning in 2026.
23 February 2024 Deals and Wins

Foley Represents rPlus Energies in $460M Partnership with Sandbrook Capital

Foley & Lardner LLP served as legal advisor to rPlus Energies, a leading private renewable energy developer, in the formation of its platform-level partnership with Sandbrook Capital, a private investment firm dedicated to transforming the world's energy infrastructure.
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.