Seth v.d.H. Cooley


  • Seth v.d.H. Cooley
  • Phone: +1 215 979 1838

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  • Duane Morris LLP
    30 South 17th Street
    Philadelphia, PA 19103-4196

Seth v.d.H. Cooley has handled complex environmental regulatory, litigation and transactional matters for more than three decades. In addition, his practice encompasses the representation of the workers compensation insurance rating bureaus.

With respect to his environmental experience, Mr. Cooley represents clients in environmental matters arising under an array of federal and state programs including the federal Clean Air Act, Superfund, Clean Water Act, and Resource Conservation, Recovery Act and Oil and Gas programs. For more than 30 years, Mr. Cooley has handled major matters for clients in the manufacturing, service, and financial sectors in environmental litigation, regulatory, and transactional matters.

For his workers compensation rating bureau clients, Mr. Cooley has provided counsel, as well as litigated cases, on a wide variety of issues over the past 30 years. In addition to serving as counsel in rate filing and classification appeal proceedings, he has advised and guided his clients on matters of policy and procedure, including bureau governance, bureau administration and legislative developments.  

Mr. Cooley's experience has ranged from serving as lead counsel for PRP groups in multi-party Superfund litigation, to defending clients in civil and criminal CAA and CWA investigation and enforcement proceedings, to representing clients in CAA Title V permit proceedings. His diverse experience has included developing and leading cutting edge challenges to the national test methods for measuring opacity of air emissions, the categorization of fugitive emissions in the context of product storage, and the joint federal/state evaluation of a leading national underground storage tank tightness test method. Mr. Cooley has also represented clients in Marcellus Shale matters in Pennsylvania.

Mr. Cooley has mediated, as counsel, numerous complex environmental disputes, and is experienced as a neutral mediator. He has been trained as a mediator at the Harvard Law School Program on Negotiation, and by the International Institute for Conflict Prevention and Resolution. Mr. Cooley has been certified as a mediator by the U.S. District Court for the Middle District of Pennsylvania, and appointed as a Judge Pro Tempore in the Philadelphia Commerce Court Case Management Program ("Commerce Court") of the Philadelphia Court of Common Pleas.

Mr. Cooley serves on the Board of the Pennsylvania Environmental Council and is a Master of the Delaware Valley Environmental American Inn of Court. He is a 1984 graduate of the University of North Carolina at Chapel Hill School of Law and a graduate of Rutgers University.

Areas of Practice

  • Environmental Law and Litigation
  • Insurance Law
  • Administrative Law

Representative Matters

    Environmental Law

  • Counsel to the owner/operator of the Ambassador Bridge between Detroit and Ontario, in connection with enforcement by the State of Michigan with gasoline vapor pressure regulations, in an action against Michigan in which Ammex is seeking declaratory and injunctive relief.

  • Counsel to natural gas operator in connection with a variety of Marcellus Shale permitting and enforcement issues in Pennsylvania.

  • Lead counsel to major national manufacturer of expandable polystyrene (EPS) food and drink containers in multi-jurisdiction (Arizona and California), precedent-setting Title V dispute related to the ability of EPA and state and local permitting authorities to categorize off-gas emissions from warehoused EPS finished products as non-fugitive in nature and therefore subject to Title V permit requirements and retroactive imposition of NSR requirements.

  • Lead counsel for major electric utility in Puerto Rico federal court proceeding involving a frontal challenge to the reference method utilized by EPA and all other air regulatory agencies to determine the opacity of air emissions - EPA Method 9. This multi-year, complex proceeding resolved favorably with a settlement affording the client extended flexibility in fuel selection.

  • Counsel to national analytical laboratory company in all aspects of the aftermath of a hazardous compressed gas cylinder explosion at the client's facility in New Jersey. The explosion resulted in multiple deaths, personal injuries, releases of hazardous gases from other hazardous compressed gas cylinders, a fire, site contamination from chemical releases exacerbated by fire water run-off, an area-wide evacuation, a class action by evacuees, personal injury, property damage and business interruption claims and litigation, insurance claims and coverage issues, a criminal investigation, and an OSHA proceeding. The representation also included an internal investigation on behalf of the client's board of directors, management of press coverage, and interaction with senior EPA Region II and NJDEP management. The criminal investigation ended without charges, and the civil proceedings were all favorably resolved.

  • Represented developer of major industrial brownfield sites in connection with pre-acquisition due diligence, risk allocation, and environmental insurance procurement, and in regard to pre- and post-acquisition voluntary and involuntary (e.g., ISRA) site investigation and remediation, disclosure obligations, PCB "Mega Rule" compliance issues, UST closure requirements, and stormwater discharge issues.

  • Counsel to developer client regarding groundwater withdrawal, allocation and permitting issues.

  • Multi-year management of post-divestiture environmental liabilities and indemnification obligations of the seller of a regional network of over 100 service station/convenience stores and ten gasoline and heating oil terminals; responsibilities include managing voluntary cleanups of contaminated bulk and retail store sites, defending penalty claims and proceedings, resolving disputes with indemnitees, negotiating access agreements, deed restrictions and property damage claims with neighboring property owners, resolving municipal wellhead protection issues, pursuing claims against other responsible parties, seeking reimbursement from available state funds, and pursuing and negotiating with insurers.

  • Representation of purchaser of commodity chemical manufacturing plants in Texas and Canada in transaction necessitating accelerated Phase I and II site and regulatory compliance assessments, negotiation of risk allocation, reporting of findings to applicable authorities, post-acquisition prosecution of indemnification claims, and ongoing oversight of the purchaser's groundwater monitoring program.

  • Representation of international heavy construction equipment manufacturer in time-sensitive acquisition of entire east coast network of distributor sales/service locations. Subsequent negotiation of environmental provisions of acquisition documents, arrangement for transfer of existing permits and authorizations, counsel in obtaining missing permits and authorizations, and guidance of post-acquisition measures necessary to bring non-compliant facilities into compliance with applicable requirements (e.g., SPCC Plans, stormwater BMPs, UST upgrades).

  • Representation of the largest volumetric contributor to major Pennsylvania CERCLA NPL site in multiple cancer death and illness cases brought by firefighters, policemen and other individuals allegedly exposed through inhalation to carcinogens during emergency response to a massive site fire. Claims were settled on terms the client found favorable following successful motion practice resulting in an order requiring plaintiffs to establish a prima facie case on causation prior to discovery.
  • Defense and resolution of aerospace industry manufacturer in multiple personal injury and property damage claims arising out of TCE ground water contamination at captive NPL site in Pennsylvania.

  • Successful representation of manufacturing client in challenges to proposed RACT regulations which would have reduced allowable VOC emissions to levels which were not achievable given the company's manufacturing processes (Arizona and California).

  • Defense and negotiation of non-admission settlement of alleged Title V permit violations relating to minimum temperature and monitoring requirements (New Jersey).

  • Counsel to leading builder of steel bridges spanning interstate highways and major water bodies in defense of alleged NSR violations associated with bridge painting operations, and in regard to Title V and synthetic minor permitting in Pennsylvania.

  • Counsel to manufacturer of dietary supplements in successful avoidance of regulation and potential enforcement under the Pharmaceutical MACT standard in connection with the client's Missouri manufacturing facility.

  • Counsel to manufacturer of plastic films in successful avoidance of sanctions associated with alleged failure to obtain a synthetic minor air permit for emissions from printing and coating operations in Illinois, and successful recovery of defense costs under indemnification agreement with a third-party.

  • Representation of Pennsylvania utility in multiple civil penalty matters arising out of alleged non-compliance with CEMS and data availability regulatory requirements.

  • Lead counsel in "bet the company" litigation for a leading national UST tank tightness testing company. Successful avoidance of criminal prosecution and successful reinstatement of license.

  • Common litigation counsel to multiple Superfund PRP groups. Successes include recovery of majority share ($10+ million) from foreign affiliate of NPL site owner/operator.

  • Representation of buyers, sellers, lenders, and investors in more than 200 transactions involving environmental due diligence, assessment and allocation of risk, and structure and guidance of site investigation and remediation programs.

  • Insurance

  • Defended the Pennsylvania Compensation Rating Bureau in an administrative hearing challenging its entire classification ratemaking methodology.

  • Represented the Delaware Compensation Rating Bureau in an appeal to the Delaware Court of Chancery from a Delaware Insurance Department order requiring retroactive premium refunds.

  • Represented the Pennsylvania Compensation Rating Bureau in more than two dozen formal classification appeal proceedings, including appeals to the Pennsylvania Commonwealth Court.


  • New Jersey
  • Pennsylvania
  • U.S. Court of Appeals for the Third Circuit
  • U.S. District Court for the Eastern District of Pennsylvania
  • U.S. District Court for the Middle District of Pennsylvania
  • U.S. District Court for the District of New Jersey
  • Supreme Court of Pennsylvania
  • Supreme Court of New Jersey


  • University of North Carolina at Chapel Hill, J.D., 1984
  • Rutgers College, B.A., 1980


  • Duane Morris LLP
    - Partner, 1994-present
    - Chair, Environmental Law Practice Group, 2000-present
    - Associate, 1984-1993

Professional Activities

  • Greater Philadelphia Green Business Program
    - Co-founder, 2009
  • Pennsylvania Environmental Council
    - Board Member, 2004-present
    - Chair, Policy Committee, 2008-present
  • Philadelphia Bar Association
    - Environmental Law Committee, Co-Chair, 1998
  • The Delaware Valley Environmental Inn of the American Inns of Court
    - Master

Honors and Awards

  • Listed in The Best Lawyers in America, 2016-2024

  • Listed in Chambers USA: America's Leading Lawyers for Business, 2020-2024
  • Listed in Best Lawyers Greater Philadelphia, 2016
  • Listed in the 2014 Legal Who's Who for Environmental Law
  • AV Preeminent® Peer Review Rated by Martindale-Hubbell®

Selected Publications

Selected Speaking Engagements

  • "Pennsylvania Well Drilling Laws and Regulations," Foxmoor Continuing Education, Plymouth Meeting, Pennsylvania, February 4, 2016
  • "Computer Modeling: Getting it Done on Time, Making it Convincing to Regulators, and Making It Persuasive to Courts," Pennsylvania Bar Institute's Environmental Law Forum, Harrisburg, Pennsylvania, April 10, 2014
  • "Fracking and Other Nontraditional Oil and Gas Developments: The New Frontier/The New Controversies," Practising Law Institute's Second Annual Energy and Environmental Law with the University of Houston Law Center, Houston, Texas, March 8, 2012
  • "Shale Gas Drilling and Development: Meeting the Legal Challenges: Best Practices for Negotiating Leases, Permitting and Addressing Environmental Issues," Stafford Publications, July 19, 2011
  • "Exploration and Production of Nontraditional Oil & Gas Resources: The New Frontier," Practising Law Institute's First Annual Energy and Environmental Law with the University of Houston Law Center, Houston, Texas, February 3, 2011
  • "Post Development and Long-Term Responsibility," Pennsylvania Environmental Council and Duquesne University Marcellus Shale Policy Conference, Pittsburgh, Pennsylvania, May 4, 2010
  • "Greenhouse Gas Emission Reporting Requirements, Look Out, Here They Come!" New Jersey Corporate Counsel Association, September 18, 2008
  • "Storage Tank Litigation," seminar sponsored by the Pennsylvania Bar Institute, Philadelphia and Pittsburgh, Pennsylvania, October 1995, and Harrisburg, Pennsylvania, November 1995 Rhode Island Bar Association
  • "1994 Environmental Law Update," seminar sponsored by the Philadelphia Bar Association, Philadelphia, PA, October 1994
  • "Transactional Issues, " Underground Storage Tanks, seminar sponsored by the Pennsylvania Bar Institute, Philadelphia and Harrisburg, PA, April 1993