Matthew Conley

Matthew Conley is a partner in the firm’s litigation and environmental law departments. Matt concentrates his practice on complex environmental, toxic tort and products liability litigation in state and federal courts. He has considerable experience prosecuting and defending claims relating to environmental contamination, including cost recovery, contribution and property diminution. Matt has particular expertise in the area of natural resource damages (NRD) and is a frequent speaker and commentator on NRD issues. Matt also has experience representing  Fortune 100 and multinational companies at large Superfund sediment sites and in response to claims relating to per- and polyflourinated alkyl substances (PFAS). Matt has conducted and managed all phases of discovery in complex litigation and has significant experience with ESI discovery.

Matt also has extensive experience advising clients on environmental regulatory matters in New Jersey, Pennsylvania, and other jurisdictions, with particular experience relating to the Site Remediation Reform Act, the Licensed Site Remediation Professional program, and the Industrial Site Recovery Act in New Jersey, RCRA corrective action, as well as the Act 2 process in Pennsylvania. Matt also has significant experience advising clients on the sale and development of commercial properties, particularly properties undergoing active remediation.

Prior to joining Archer, Matt worked for the New Jersey Department of Environmental Protection as a Case Manager in the ISRA department.

Representative Experience


  • Served as trial counsel in Pennsylvania for a Fortune 5 company defending claims involving property diminution and cleanup costs, obtaining a complete defense verdict dismissing all claims against his client. Involved novel questions relating to liability and hydrogeology.
  • Represents a major petroleum company in several jurisdictions, including New Jersey, Puerto Rico, Maryland, Rhode Island and others, defending product liability and natural resource damage claims associated with gasoline additive methyl tertiary butyl ether (MTBE).
  • Represents a large petrochemical company in action brought by the New Jersey Department of Environmental Protection (NJDEP) seeking NRD for alleged injury to surface water, groundwater, wetlands, biota and sediments at a former refinery.
  • Represents a natural gas utility in defense of NRD action brought by NJDEP for alleged injury caused by historic manufactured gas plant.
  • Represented an international chemical company in defense of a multi-billion dollar action filed by NJDEP for environmental cleanup costs and other damages associated with the Passaic River and the Newark Bay Complex.
  • Represented a major petrochemical company in New Jersey defending and prosecuting claims involving property diminution, cleanup costs, and fraudulent conveyances.
  • Represented a major petroleum company defending toxic tort, medical monitoring, property diminution and other claims relating to a large release in Maryland.


  • Advise regulated parties regarding upcoming or recently adopted regulatory or legislative developments, including EPA final rules regarding environmental due diligence, UST equipment standards, and recent revisions to DOT regulations.
  • Advise various clients to ensure compliance with regulatory requirements regarding site remediation strategies, including proposed maximum contaminant limits, notification requirements and risk-based corrective action.
  • Represent numerous parties before federal and state agencies in enforcement matters, including information requests, penalty assessments, and consent decrees.
  • Address permitting issues, including NPDES permits, Title V permits, wastewater pre-treatment, UST registration, and soil erosion and sediment control.


  • Draft, negotiate and enforce environmental remediation and indemnity agreements in the context of industrial and commercial property transfers.
  • Advise parties entering commercial agreements, including methodologies for limiting and assigning environmental risks.
  • Advise a major petroleum company on complex commercial transactions involving the sale of hundreds of properties with known or potential environmental impacts.
  • Advise parties on compliance with Industrial Site Recovery Act.

Professional and Community Involvement

  • Master and Executive Board Member, Stewart G. Pollock Environmental American Inn of Court (2017-present)
  • Delaware Valley Environmental American Inn of Court
  • Board Member, National Multiple Sclerosis Society (2018-present)
  • American Bar Association-Environmental, Energy and Resources Section
  • New Jersey State Bar Association
  • Pennsylvania Bar Association
  • Philadelphia Bar Association
  • Co-Founder; Executive Editor, Seton Hall School of Law Circuit Review (2004-2006)

Articles and Presentations

  • Co-Author, “NJ’s Natural Resource Damage Order May Be Helpful For Cos.,” Law360 (April 2023)
  • Co-Author, “NJDEP Issues Administrative Order Revamping NRD Settlement Policies and Practices in New Jersey,” Archer & Greiner, P.C. Client Advisory (March 2023)
  • Author, “Pa. Steps Up NRD Enforcement. Is a Comprehensive NRD Program Coming?,” The Legal Intelligencer (July 2022)
  • Speaker, Considerations for Compensating Injuries in NRD Litigation, New Jersey State Bar Association’s Environmental Law Forum (June 2021)
  • Co-Author, “The Power of Private Actions For Natural Resource Damages“, Law360 (November 2020)
  • Co-Author, Natural Resource Damages Chapter, New Jersey Environmental Law Handbook (9th edition), Bernan Press (February 2020)
  • Speaker, NRD and Other Subjective Damages, Perrin Environmental Risk & Litigation Conference (June 2019)
  • Speaker, New Jersey Department Environmental Protection Renewed NRD Program: NRD Practitioners Update, Chemistry Council of New Jersey Spring Conference (May 2019)
  • Author, “New Jersey Court Dismisses NJ DEP Claims in NRD Case,” Archer Client Alert (December  2018)
  • Speaker, Latest Insights Regarding Natural Resource Damages Program, LSRP Summit (December 2018)
  • Author, “New Jersey Ramps-Up NRD Program under Governor Murphy” (August 2018)
  • Author, “GenX: Recent Regulatory and Litigation Developments,” American Bar Association (July 2018)
  • Author, “New Jersey’s NRD Program Likely to Ramp-up Under Governor Murphy,” Archer Client Alert (February 2018)
  • Speaker, Property Tax Assessments for Contaminated Properties and Industrial Facilities, Chemistry Council of New Jersey Spring Conference (May 2017)
  • Author, “The Innocent Purchase Defense (and Offense) in the LSRP Era,” New Jersey Law Journal (November 2014)
  • Author, “Spill Act Liability for ‘Innocent’ Owners of Contaminated Property,” New Jersey Law Journal (November 2010)


Matthew Conley Co-Authors Natural Resource Damages Chapter of New Jersey Environmental Law Handbook

Marc Rollo, Matthew Conley and Charlie Dennen Co-Author Law360 Article, "NJ's Natural Resource Damage Order May Be Helpful For Cos."

Archer Attorneys Present at NJSBA Environmental Law Forum 2021