John McGahren
John McGahren is the Princeton litigation practice leader and deputy chair of the firm’s global environmental practice. John counsels clients on litigation, enforcement, and transactional matters. He prosecutes and defends citizen suits, Superfund and RCRA disputes, Clean Water and Air Act litigation, state law actions, and natural resource damage claims. He represents clients in commercial litigation, products liability, toxic tort, class actions and government contract claims. John frequently provides counsel on US federal and state regulatory matters and investigations.
John served as a federal mediator for the District of New Jersey and as a state mediator for the New Jersey Supreme Court Civil Mediation Program. As part of his volunteer work, he has been a member of the board of directors of NJ Law and Education Empowerment Project, which empowers urban youth from underserved neighborhoods to perform at high academic levels.
Before practicing law, John was a licensed professional engineer in the US Environmental Protection Agency Region II Superfund program, working on sites in New York, New Jersey, and Puerto Rico.
Litigation
- Represent a paper mill client in administrative and litigation proceedings with the US Environmental Protection Agency (EPA) and the South Carolina Department of Health and Environmental Control (SCDHEC), including issuance of one of only five emergency orders ever issued by EPA under the Section 303 of the Clean Air Act (CAA)
- Represent paper mill in follow-on litigation brought by residents and businesses surrounding the mill, including three citizen suits under the Clean Air Act, the Clean Water Act, and the Resource Conservation and Recovery Act (RCRA), as well as three class action odor lawsuits. The plaintiffs seek to certify a class of residents and businesses located within a 20-mile radius of the mill, which would include over a million potential class members.
- Providing for paper mill client regulatory and compliance counseling on site remediation, SCDHEC administrative consent orders, EPA consent decrees, closure of sludge ponds, solids management plans, air and wastewater treatment system upgrades, and responses to EPA and SCDHEC notices of potential violations
- Handling a US Court of Appeals for the Fourth Circuit appeal involving a case of first impression on intervention under Section 303 of the CAA
- Represent telecommunications company in multiple litigations in Nassau County, New York, alleging contamination to groundwater and soils from radionuclides and chlorinated solvents stemming from work performed by predecessor companies on behalf of the US Atomic Energy Commission, as well as alleged contamination of groundwater and municipal wells from emerging contaminants, including 1,4-dioxane and per- and polyfluoroalkyl substances (PFAS)
- Represented an automobile manufacturer in two related Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and New Jersey Spill Act cost recovery and contribution actions in the US District Court for the District of New Jersey for costs associated with removal and remediation of polychlorinated biphenyl (PCB)-contaminated, recycled concrete used as fill by a developer on multiple properties in New Jersey, as well as other statutory, contractual and common law damages claims
- Provided compliance counseling to automobile manufacturer on decommissioning and cleanup of the auto manufacturing facility, which exceeded $100 million
- Represent former chrome plating manufacturing client in defense of environmental cost recovery and natural resource damages (NRD) action brought in late 2018 by the New Jersey Department of Environmental Protection (NJDEP) as part of the larger “environmental justice” initiative by New Jersey; the matter involves alleged chromium contamination at the Puchack Well Field Superfund Site in Pennsauken, New Jersey
- Represent manufacturing clients in defense of NRD lawsuit brought by the NJDEP, stemming from alleged discharge of hazardous substances, including trichloroethylene (TCE) and perchloroethylene (PCE), at a three-acre former tool and die manufacturing facility in Montvale, New Jersey, which migrated into groundwater beneath the facility and contaminated multiple municipal drinking wells
- Represent the US Department of Energy’s current and former contractor operators of the Brookhaven National Laboratory on Long Island in toxic tort cases involving alleged exposure to chlorinated solvents and radionuclides, which were brought in the Eastern District of New York
- Represent a paper manufacturer in indemnity action in New York Supreme Court for recovery of environmental costs attributable to a former mill operator’s bleaching process, which generated dioxin as a byproduct
- Represent a manufacturing company in an indemnity action in New York Supreme Court concerning recovery of costs for the El Monte Operable Unit of the San Gabriel Valley Superfund site in Los Angeles
- Obtained dismissal of a prior action regarding the same costs brought in Los Angeles Superior Court, based upon a New York forum selection clause in the operative agreement and obtained dismissal of a recission counterclaim asserted in the New York action
- Represented an environmental and engineering consulting firm on design and construction dispute before the American Arbitration Association involving increased costs for alleged unknown subsurface conditions encountered in construction of a slurry wall on a contaminated site in Massachusetts
- Represented a real estate development and investment company in CERCLA cost-recovery litigation against the United States for contamination stemming from WWII-era munitions production for the US military in Cranbury, New Jersey before the Third Circuit
- Represented real estate developer in New Jersey Chancery Court involving alleged breaches of loan agreements and successful defense of temporary restraining order and preliminary injunction proceedings
- Represented national water purveyor in putative class action in the Southern District of New York alleging violations of New York General Business Law § 349, breach of contract, unjust enrichment, negligence, and fraud
- Represent chemical manufacturing company against cost recovery claims by the University of Minnesota under CERCLA and the Minnesota Environmental Response and Liability Act stemming from WWII-era ordnance production on behalf of the United States on land that was acquired by the university post-war
- Represent international chemical company in class action litigation brought in Philadelphia Court of Common Pleas arising from a chemical spill in the Delaware River seeking damages for nearly one million potential class members who consume water from the Baxter Water Treatment Plant in North Philadelphia, with the case recently removed to federal court
- Assisting international chemical company on compliance counseling with multiple regulatory agencies that responded to chemical spill in Delaware River
- Represented national energy provider in over 500 cases in the Eastern District of Missouri and Missouri state court involving radionuclide exposure claims under the Price Anderson Act and state law for alleged personal injury and property damage in St. Louis County; settled the federal case for an amount less than the estimated defense costs for taking the cases to trial
- Represent a paint manufacturer in connection with three Superfund sites in Gibbsboro, New Jersey, which are contaminated with lead and arsenic, and provide compliance counseling and regulatory support for the cleanups with EPA and NJDEP, including dredging of major lakes and surface water bodies contaminated with lead and arsenic, as well as advise on vapor intrusion and future site redevelopment issues
- Represent a paint manufacturer in connection with the Passaic River litigation, which includes ongoing CERCLA cost recovery and contribution litigation for the upper 9 and lower 8.3 miles of the river, and advising the client on a consent decree with EPA
- Represent paint manufacturer in a suit brought by NJDEP for the Avenue P site in New Jersey, which was styled as an environmental justice action for penalties and injunctive relief by the Commissioner of NJDEP
- Represented the World Trade Captive Insurance Company, the City of New York, and over 100 response contractors against personal injury and property damage claims in the multidistrict litigation (MDL) in the Southern District of New York related to toxic dust cloud and debris removal and clean-up activities that occurred after the 9/11 terrorist attacks
- Represented property owner in litigation in New Jersey Superior Court in Bergen County stemming from breach of lease by client’s tenant involving historic riverboat, which sank in the Hudson River during Superstorm Sandy and obtained a summary judgment victory requiring the tenant to reimburse the property owner for hundreds of thousands in lost rent and costs
- Represented property owner in litigation against a tenant who defaulted on their lease for a major restaurant development after the pandemic
- Represented petroleum company in Toxic Substances Control Act (TSCA) citizen suit in Puerto Rico and obtained dismissal on a motion to dismiss
- Served as common counsel and represented 17 companies in a CERCLA cost recovery and contribution litigation with the United States for a major Texas Superfund site, which was the site of a former tin smelter owned and operated by the United States and later converted for different metals smelting operations. The representation led to the assignment of a major share of responsibility to the United States for cleanup costs and natural resource damages.
- Worked with EPA and federal and state natural resource trustees on the selection of remedial investigations and actions, which were integrated with natural resource damage assessment and restoration projects
- Served as lead trial counsel in a successful declaratory judgment suit on behalf of a chemical company in the US District Court for the District of New Jersey. The company filed suit against the current property owner for contractual indemnity for all potential liability and costs, including natural resource damages associated with EPA and NJDEP Passaic River initiatives; argued in the Third Circuit, which affirmed the district court's decision.
- Served as trial counsel for a private company and an individual in a RCRA citizen suit against the commissioner of NJDEP, where the district court found the commissioner liable; NJDEP subsequently settled with the clients and released them from any further cleanup responsibility; also obtained a liability ruling under RCRA and CERCLA against the United States and argued in the Third Circuit.
- Represented an automobile manufacturer in a CERCLA contribution action in District of New Jersey against the United States for 16 former defense plant facilities located in several states and procured multimillion dollar settlements
- Obtained a ruling from the US Court of Appeals for the Federal Circuit on behalf of a major chemical manufacturer upholding indemnification from the United States for 100% reimbursement of attorney fees and environmental cleanup costs arising from the construction and operation of a WWII ordnance plant in West Virginia
- Defended a real estate investment trust in multidistrict litigation in the Southern District of New York involving claims for contamination of public water supply wells with the gasoline additive methyl tertiary butyl ether (MTBE)
- Defended a chemical manufacturer and dry cleaning equipment manufacturer against claims brought in New York Supreme Court by large water purveyor for contamination of wells with dry cleaning solvents. Obtained early settlements for both clients on favorable terms
- Defended a chemical manufacturer against claims brought by workers in 18 counties in West Virginia for exposure to PCE in mining float sink testing laboratories and obtained early settlement on favorable terms
- Represented a chemical manufacturing and oil company in a multisite CERCLA action against the United States in the District of New Jersey and before the Third Circuit three-judge and en banc panels in an appeal of the district court's order denying the companies' right to seek cost recovery from the United States for 14 contaminated sites in eight states. Filed a petition for certiorari to the US Supreme Court, which was granted, but the Court elected to proceed with a concurrently filed petition addressing the same issues in Atlantic Research v. United States.
- Represented a major electronics manufacturer in a contract action against the United States in the US Court of Federal Claims for defense costs and indemnification for cleanup costs arising from the operations of a former nuclear fuel cell manufacturing facility in Massachusetts, which was utilized by the Atomic Energy Commission, the US Navy, and various national laboratories
- Submitted amicus briefs to the US Supreme Court in Cooper Industries Inc. v. Aviall Services Inc. and Atlantic Research v. United States on behalf of private companies
- Represented a New Jersey township in a RCRA citizens suit against the state for cleanup of a large former state hospital complex and negotiated a settlement where the state transferred ownership of the facility to the township, which required approval of the state legislature and the governor
- Prosecuted claims of a chemical company in the District of New Jersey under the New Jersey Consumer Fraud Act arising from false representations related to fire and explosion from newly installed dust collection and fire suppression systems. Representation also included defense in related state court litigation involving products liability, Consumer Fraud Act claims and common law claims.
- Represented a portfolio power company in New York Supreme Court and New York Appellate Division on indemnity claim under purchase and sale agreement for seven power plants for breach of representations and warranties on operation and maintenance practices by seller
Enforcement and Administrative Proceedings
- Represented numerous clients in TSCA audits and inspections, test orders, and enforcement proceedings
- Represent a silverware manufacturer in consent decree negotiations for soil and groundwater cleanups of chlorinated solvents at the San German Superfund Site in Puerto Rico and negotiated a consent decree with EPA for the Operable Unit 1 soil cleanup. Advised the client on vapor intrusion and other regulatory compliance issues, as well as insurance coverage options.
- Represented mining and energy companies in connection with the investigation and remediation of a multi-party Superfund site involving low-level radioactive materials originating from Manhattan Project operations, including negotiations with the EPA and the US Department of Justice
- Represented mining and energy companies in connection with a related multi-party cost-recovery claim by the United States for cleanup performed under the Formerly Utilized Sites Remedial Action Program (FUSRAP) at a nearby storage property, also involving low-level radioactive materials originating from Manhattan Project operations
- Advising a major international manufacturing company in evaluating operations at multiple US facilities for use of PFAS in products and supply chain
- Represented a major manufacturing company in connection with its entry into an administrative consent order with NJDEP to address an urban waterway contaminated with TCE, as well as Spill Fund and natural resource damages claims
- Serve as common counsel to the BROS Superfund site providing regulatory and compliance counseling for a massive ongoing groundwater cleanup involving numerous chemicals and emerging contaminants such as 1,4-dioxane and PFAS
- Represented a major sports company and stadium in Massachusetts in negotiation of an administrative order with MassDEP addressing alleged solid waste and recycling violations arising from stadium operations
- Represent an electronics manufacturer in connection with a cross-border chlorinated solvent plume in Massachusetts and Rhode Island, which allegedly contaminated residential wells in the area. Conducted negotiations and counseled the client concerning installation of alternative water supply lines across state lines, which involves multiple state environmental agencies and municipalities
- Represent a retail electric and natural gas company in license revocation proceedings initiated by the Texas and Pennsylvania Public Utility Commissions. Obtained summary judgment dismissal before Pennsylvania hearing examiner, which is currently under appeal. Settled the Texas proceeding on favorable terms
- Represented a chemical manufacturer regarding a Superfund/Formerly Utilized Sites Remedial Action Program (FUSRAP) site in New Jersey where thorium had been produced. Retained to enforce a cooperative agreement between the company and the US Department of Energy. Negotiated a settlement with the United States for the FUSRAP radiological cleanup, with total estimated costs in excess of $500 million. Also represented the company in a parallel Superfund cleanup of chemical contaminants as well as Nuclear Regulatory Commission licensing and decommissioning proceedings
- Represented an automobile manufacturer in civil and criminal proceedings associated with the decommissioning and demolition of an automotive assembly plant in New Jersey, where the state alleged the company violated numerous provisions of the New Jersey Solid Waste Management and Spill Acts at multiple sites. Negotiated an administrative consent order with NJDEP settling the company's liability to the state
- Represented a chemical manufacturer in parallel investigations by the US Chemical Safety Board and OSHA arising from a fire and explosion of a dust collection system, which severely burned workers at the facility
- Represented a major online retailer in multiple Occupational Safety and Health Administration (OSHA) investigations for worker deaths at facilities in New Jersey and Pennsylvania, including follow-on personal injury lawsuits
- Represented a major oil company in enforcement proceedings by EPA for a Superfund site in Los Angeles. Also represented the company on claims against the United States for contamination attributable to a former WWII synthetic rubber plant owned and operated by the United States at the site
- Defended a major oil company in Puerto Rico in numerous matters, including a $75 million penalty assessed for underground storage tank violations. Filed a Section 1983 civil rights action against the Puerto Rico Environmental Quality Board (EQB) on grounds of actual and structural bias in the penalty proceeding and obtained a permanent injunction barring any penalty. The matter included preliminary injunction hearings, appeals to the First Circuit and the Puerto Rican Supreme Court, as well as hearings in the Puerto Rican Senate. Obtained a permanent injunction against the EQB on the penalty. We also defended the client in related toxic tort cases, which were dismissed
- Represented a chemical manufacturer in a TSCA PCB Mega Rule petition for a risk-based cleanup of one of its former facilities in New Jersey-the second PCB Mega Rule petition ever approved by EPA Region II. Negotiated a remedial action work plan and liability buyout proposal with NJDEP, which included a bankruptcy court-approved natural resource damages settlement
- Represented a national hazardous waste disposal company in negotiations with NJDEP concerning the siting of a solid and hazardous waste rail transfer facility in New Jersey and the settlement of alleged A-901 violations
- Represented a chemical company in municipal hearings concerning a manufacturing plant in New Jersey, where a municipality was seeking to designate the property as an area in need of redevelopment along the lines addressed by the US Supreme Court decision in Kelo v. New London
- Represented a power company in obtaining a Title V and Prevention of Significant Deterioration (PSD) permit for a proposed gas turbine power plant in New Jersey
- Negotiated a carbon monoxide emissions offset trade required for air permits with a major airline
- Conducted a Foreign Corrupt Practices Act and UK Bribery Act internal investigation for a foreign company involving practices in numerous foreign countries. Advised the client on corporate compliance and ethics programs and anti-corruption policies
Pro Bono Litigation
- Lead pro bono trial counsel for public interest groups and individual plaintiffs in a New Jersey Superior Court action asserting constitutional and statutory challenges to the state's use of paperless direct recording electronic voting machines. The case involved a lengthy trial and appeals to the New Jersey Superior Court, Appellate Division, and the New Jersey Supreme Court.
Transactions
- Represent clients in due diligence investigations on environmental issues in numerous corporate and real estate transactions and financing matters
- Represent clients in Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) subregistration and data sharing agreements and pesticide and anti-microbial registration proceedings
- Represent the Port Authority of New York and New Jersey on environmental, regulatory and contracting for major infrastructure and energy projects at airports and other facilities
- Represented a chemical manufacturer in connection with Chapter 11 proceedings for a third-party liability buyout of a former facility heavily contaminated with PCBs. Identified the requirements for the buyout; assisted on contractor selection; drafted and negotiated the liability buyout contract with the contractor and a settlement agreement with the state, which included settlement of natural resource damages; and negotiated the insurance policy as financial assurance for the buyout.
Alternative Dispute Resolution
- Acted as federal mediator in a trade agreement breach and trademark infringement matter, the first joint mediation of its kind involving mediators appointed by District of New Jersey and the Third Circuit
- Served as a state court mediator in an action asserted by NJDEP
- Served on American Arbitration Association panels of arbitrators and mediators in numerous matters involving construction, commercial, and environmental disputes
- Served as court-designated mediator in numerous commercial, environmental, and other matters in the District of New Jersey's mandatory mediation program
- Served as court-designated mediator in numerous civil litigation matters in the New Jersey Supreme Court Civil Mediation Program
Results may vary depending on your particular facts and legal circumstances.
- New York Law School, 1990, J.D.
- Manhattan College, 1986, B.S., magna cum laude
- Manhattan College, 1986, M.S., magna cum laude
- New Jersey
- New York
- West Virginia
- US Supreme Court
- US Court of Federal Claims
- US Court of Appeals for the Federal Circuit
- US Court of Appeals for the First Circuit
- US Court of Appeals for the Second Circuit
- US Court of Appeals for the Third Circuit
- US Court of Appeals for the Fourth Circuit


Listed, Leaders in Environmental Law, Environmental Litigation, Lawdragon Green 500 (2023–2025)
Listed, Lawdragon 500, Leading Environmental & Energy Lawyers (2021)
Listed, The Best Lawyers in America, Lawyer of the Year, Environmental Law, Princeton (2019, 2022)
Listed, The Best Lawyers in America, Litigation – Environmental, Princeton (2024–2026)
Listed, The Best Lawyers in America, Environmental Law, Princeton (2017–2026)
Band 1, Environment, New Jersey, Chambers USA (2021–2025)
Ranked, Environment, New Jersey, Chambers USA (2006–2020)
Leading Lawyer, Industry focus: Environment: litigation, The Legal 500 US (2022–2024)
Recommended, Environment: litigation, The Legal 500 US (2020, 2021, 2025)
Recommended, Environment: regulatory, The Legal 500 US (2016–2025)
Recommended, Industry focus: Energy litigation: electric power, The Legal 500 US (2023, 2024)
Recommended, Industry focus: Energy litigation: oil and gas, The Legal 500 US (2023, 2024)
Recommended, Industry focus: Energy litigation: conventional power, The Legal 500 US (2020–2022)
Recommended, Dispute resolution: Product liability, mass tort and class action - defense: toxic tort, The Legal 500 US (2020)
Member, Law360, Practice Group of the Year, Environmental (2017, 2019)
Listed, Super Lawyers Business Edition (2011–2013)
Listed, New Jersey Super Lawyers (2006–2013)
Past Member, Panel of Arbitrators and Mediators (1992) and Environmental Panel (1997), American Arbitration Association
Member, West Virginia Bar Association
Member, US Court of Federal Claims Bar Association
Past Member, American Society of Civil Engineers
Past Member, American Water Works Association
Licensed Professional Engineer, New York (1989)
Certified, OSHA Hazardous Materials Handling (1986)
No aspect of this advertisement has been approved by the Supreme Court of New Jersey. A description of the selection methodology for the above awards can be found here.
