Barclay Damon
Barclay Damon

Yvonne E. Hennessey

Yvonne E. Hennessey


p: 518-429-4293

f: 518-427-3472

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Albany Office

80 State Street
Albany, New York 12207

Yvonne Hennessey is a Partner in our Energy, Environmental, Regulatory and Commercial Litigation Practice Areas and serves as Co-Chair of the Environmental Practice Area, as well as Chair of the Lobbying & Election Law Compliance Practice Area. Yvonne represents commercial and industrial clients, primarily in the energy arena, on a wide range of environmental matters involving civil litigation, federal and state permitting, compliance, civil and administrative enforcement, and government relations.

She also represents clients in the oil and gas sector on a broad variety of issues involving well permitting and project siting, air aggregation and water withdrawals, compulsory integration, administrative adjudication, civil litigation, legislation, lobbying compliance and investigations by the New York State Attorney General’s office.

Yvonne has assisted corporate clients, both large and small, in a variety of matters including those related to the Clean Air Act (CAA) and related state regulations, the Clean Water Act (CWA), the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA), the Resource Conservation and Recovery Act (RCRA), the New York State Coastal Management Program, the National Environmental Policy Act (NEPA), the New York State Environmental Quality Review Act (SEQRA), and other state and federal environmental statutes and regulatory programs that apply to project permitting and siting.

Yvonne has also represented clients in every aspect of complex litigation in a broad range of litigation matters, including commercial, regulatory and leasing disputes. Her litigation work includes extensive experience in both state and federal court, including CERCLA actions and challenges under SEQRA, and her regulatory work includes election, ethics, and lobbying law compliance.

Yvonne is the lead contributor to the firm's blog Energy Matters: Energy Law Updates and Observations. Yvonne is an active member of the firm's Women's Forum.

Representative Experience

  • Represent an interstate pipeline company proposing to construct a new 120-mile interstate gas pipeline which will connect a Marcellus Shale gas gathering system in Susquehanna County, PA, to interstate natural gas transmission pipelines in Schoharie County, NY.
  • Represent a major energy company is pending litigation involving preemption under the Federal Power Act.
  • Represent a number of commercial clients in Article 78 challenges, defending permits issued by the New York State Department of Environmental Conservation as well as other state and local agencies.
  • Represented a company in a CERCLA action in the Western District of New York relative to alleged radioactive waste contamination and negotiated a successful settlement agreement.
  • Successfully defended a landfill operator in a legal challenge to a New York State Department of Environmental Conservation permit both before the lower court and on appeal.
  • Participated in all aspects of federal and state permitting processes, including Title V and State Pollution Discharge Elimination System permitting, as well as significant environmental review under SEQRA, for electric generating, manufacturing and multiple solid waste management facilities.
  • Advise clients on water withdrawal issues, including permitting before the Susquehanna River Basin Commission and the Delaware River Basin Commission as well as under New York State's new water withdrawal statute.
  • Involved in the 2008 amendments to the Environmental Conservation Law to accommodate shale development in New York, including the Marcellus and Utica shales. 
  • Represented industry working group in the environmental review process conducted by the New York State Department of Environmental Conservation as part of its development of a Supplemental Generic Environmental Impact Statement relative to high-volume hydraulic fracturing.    
  • Represent a large interstate pipeline company and industry working group before the United States Army Corps of Engineers to help streamline the permitting process for linear energy projects.  
  • Part of a legal team that successfully represented a national company in connection with the resolution of multi-million dollar claims under CERCLA and New York’s navigation law and common law nuisance doctrine.   
  • Worked with nationally renowned experts in the field of public health as part of a particulate matter air impact analysis for the siting of a cement manufacturing plant.  
  • Represented current owner of a State Superfund and hazardous waste site in disputes with the New York Department of Environmental Conservation relative to the need for additional site remediation as well as with prior site owners regarding contractual responsibility for clean-up.
  • Represented various natural gas operators in force majeure lease disputes stemming from the current moratorium in New York on high-volume hydraulic fracturing.
  • Represent commercial clients, including natural gas operators relative to road use agreements with local municipalities. 
  • Engaged in a thorough analysis of environmental justice issues relating to a proposed siting project in New York which resulted in a detailed report finding no environmental justice concerns. 
  • Drafted a comprehensive coastal zone consistency analysis for a proposed siting project, as well as a detailed permit application to the United States Army Corps of Engineers. 
  • Obtained multiple injunctions from a federal court against newly adopted New York State regulations. 
  • Engaged in a thorough audit of a major energy provider’s election and lobbying law compliance and provided similar companies with legal advice as to permissible election and lobbying activities. 
  • Successfully assisted clients in organizing political action committees for federal, state and local election activities.

Practice Areas


  • State University of New York at Geneseo, B.A., 1993
  • Northeastern University School of Law, J.D., 1997

Admitted To Practice

  • New York, 1997
  • Pennsylvania
  • Massachusetts
  • U.S. Court of Appeals, 2nd Circuit
  • U.S. District Court, Northern District of New York
  • U.S. District Court, Western District of New York
  • U.S. District Court, Southern District of New York
  • U.S. District Court, Eastern District of New York
  • U.S. District Court, District of Massachusetts

Memberships & Affiliations

  • Immediate Past-President, Northern District of New York Federal Court Bar Association (2013-2014)
  • Member, Energy & Mineral Law Foundation
  • Member, Independent Oil & Gas Association of New York
  • Member, New York State Bar Association Environmental Law Section’s Executive Committee; Co-Chair of Section's Energy Committee
  • Member, Capital District Women’s Bar Association 
  • Member, Women's Bar Association of the State of New York 
  • Member, Albany County Bar Association 
  • Walk Director and Co-Chair of Corporate Sponsorships, Northeastern New York Susan G. Komen Race for the Cure, 2007 and 2008 
  • Member, Eastern New York Chapter, Air & Waste Management Association

Speaking & Publications

  • Author, Energy Blog
  • "NY Water Withdrawal Just Got Easier For Power Generators," Law360, October 23, 2014
  • Presenter, "Aggregation of Air Emissions - What Does Adjacency Really Mean?" Hiscock & Barclay Webinar, June 25, 2014
  • Keynote Speaker, "Shale Development: A Comparison of How States Are Regulating Hydraulic Fracturing," North Atlantic Chapter of the Society of Environmental Toxicology and Chemistry, 20th Annual Meeting, June 12, 2014
  • Presenter, "Aggregation of Air Emissions - What Does Adjacency Really Mean?," AWMA Oil and Gas Environmental Compliance Conference, May 14, 2014
  • "Drill Baby Drill!: NY State's Fracking Future," Law360, January 9, 2014
  • Presenter, "Mineral Rights: What Every Mineral Owner and Lessee Need to Know Now!" NBI Seminars, December 11, 2013
  • Presenter, "Hydraulic Fracturing Overview and Potential Areas for Risk," Thinking About Insureds Who Transport Waste Water Resulting from Fracking Operations Seminar, November 12, 2013
  • Presenter, "Aggregation of Air Emissions - What Does Adjacency Really Mean?" IOGANY Annual Meeting, November 6, 2013
  • Presenter, “Shale Development in New York: A Regulatory Update and Comparison with Neighboring States,” Association for Environmental Health and Sciences Foundation 29th Annual International Conference on Soils, Sediments, Water, and Energy, October 24, 2013
  • Moderator, "Which Court? State or Federal and Why? Selecting Your Jurisdiction," New York State Federal Judicial Council Advisory Committee CLE, October 22, 2013
  • Energy Matters: Energy Law Updates and Observations,” Blog Author, Hiscock & Barclay
  • “Hot Topics in Real Property Law 2013,” NYSBA CLE, September 19, 2013
  • “Flaws In NY Court's Ruling Of Recent Natural Gas Cases,” Law360, May 7, 2013
  • “New York Legal Update,” IOGANY Pipeline, Spring 2013  
  • “Increasing Federal Regulation: NY Shale Development - Part 2,” Law360, February 4, 2013
  • “Finally Ready To Drill: NY Shale Development - Part 1,” Law360, January 22, 2013
  • Speaker, Expert Fracking Panel Sponsored by the Greater Binghamton Chamber of Commerce, January 3, 2013
  • “New York Legal Update,” IOGANY Pipeline, Winter 2012
  • Presenter, Women in Communications & Energy Conference, January 2013
  • “Don't Bet On Force Majeure In NY Oil And Gas Leases,” Law360, November 29, 2012
  • Presenter, “New York's Shale Resources: A Discussion of Issues for 2013,” Associated General Contractors of NYS, November 28, 2012
  • Presenter, “Regulatory Update: Year 5 of the SGEIS and All Other Things New York,” IOGANY; Cross-Border Panelist on U.S. Regulatory Issues, October, 2012
  • “Federal Court Defines Adjacency,” IOGANY Pipeline, Fall 2012 
  • Speaker, “Industry Perspective on Marcellus Shale,” NYSBA CLE June 15, 2012
  • “The Status of Local Preemption under ECL § 23-0303(2),” IOGANY Pipeline, Spring 2012
  • Speaker, “Industry Perspective on Marcellus Shale,” SUNY Albany, March 2012
  • Speaker, “Industry Perspective on Road Use Issues,” Joint Landowners Coalition Road Use Seminar, October 2011
  • Speaker, “Marcellus Shale: An Overview,” Southern Gas Association, February 2010
  • Moderator and Speaker, “Marcellus Shale: A Primer on Mineral Rights, Leasing and Compulsory Integration,” NYSBA, October 2009
  • Speaker, “High Volume Hydraulic Fracturing of Marcellus Shale in New York,” Air, Waste & Management Association, September 2009
  • Speaker, “The Redevelopment of Contaminated Property: New York State's Brownfield Program and Beyond,” NYSBA, June 2009
  • Speaker, “New Ethics Rules for Environmental Lawyers,” NYSBA CLE, April 2009
  • “New Attorney Rules of Professional Conduct Take Effect April 1, 2009,” NYSBA, Spring 2009
  • Co-author, “How to Try a Commercial Case: The Direct Examination,” NYSBA CLE 2001
  • Co-author, “Environmental Justice, Public Participation and Standing Under the State Environmental Quality Review Act,” Albany Law School Symposium 2001


  • The Best Lawyers in America, 2013-2018 for Litigation - Environmental
  • Selected by Peer Review for Inclusion in Super Lawyer Directory 2013-2017 for Energy and Environmental
  • Recognized by the New York State Bar Association in September 2010 as one of the "brightest young members" of the Environmental Law Section

Prior Experience

  • Hiscock & Barclay, LLP, Partner
  • The West Firm 
  • O’Connell & Aronowitz 
  • LeBoeuf, Lamb, Greene & McRae 
  • Confidential Law Clerk, the Honorable Frederick J. Scullin, Jr. (former Chief Judge) and the Honorable Norman A. Mordue (Chief Judge), United States District Court for the Northern District of New York, 1998-1999. 
  • Assisted the Honorable Frederick J. Scullin, Jr. when he sat by designation on the United States Court of Appeals for the Second Circuit, 1999.