Bonnie Allyn Barnett

Phone: (215) 988-2916 (215) 988-2916
Fax: (215) 689-4257


Bonnie Allyn Barnett combines an active environmental litigation practice with counseling on regulatory compliance and the environmental implications of a wide range of business and real estate transactions. Bonnie is currently a managing partner of the firm and was the chair of the Environment and Energy Group for more than 20 years.  

From large, multi-party clean up cases to toxic tort class actions as well as contractual disputes over environmental liabilities, Bonnie has handled it all. With more than thirty years of experience, Bonnie defends clients in enforcement actions, both administrative and judicial, and citizens suits under a variety of federal and state environmental statues including the Clean Air Act, Clean Water Act, TSCA and RCRA.

Bonnie advises a diverse array of clients, from major pharmaceutical, energy and manufacturing companies, to universities and small businesses, on a full range of environmental issues. In addition to regulatory compliance advice, Bonnie routinely directs environmental assessments and audits and has worked extensively with consulting and engineering firms.


  • Negotiated the largest stipulated penalty assessed under a Superfund Consent Decree, reducing the proposed penalty by nearly half.
  • Successfully defended a utility in an enforcement and citizens’ suit over a major spill from an ash basin.
  • Defends clients in tort actions claiming damages arising from contamination, either on-site or on adjacent real property.
  • Has spent more than a twenty years working on the next environmental frontier – large and complex sediment sites. Bonnie is currently involved in several significant sediment sites on the East Coast.
  • Has represented parties at other types of cleanup sites along the East Coast from Boston to Florida and in the Midwest, as well as throughout Pennsylvania and New Jersey.
  • Has litigated a number of private party cleanup matters, including a cost recovery and contract dispute over one of the largest Superfund sites in Pennsylvania.
  • Often directs efforts to identify additional "responsible parties" at Superfund sites and is involved in allocation disputes, whether through litigation, arbitration or mediation.
  • Has negotiated dozens of consent decrees and administrative consent orders at both the federal and state level as well as settlements in private cost recovery actions.
  • Has represented clients in nationwide corporate audits under various Federal statutes, helping clients take full advantage of audit disclosure policies, to come into compliance and minimize penalty exposure.
  • Assists clients with the sale and redevelopment of environmentally sensitive property, taking full advantage of brownfields programs.
  • Helps industry clients establish internal compliance auditing programs to resolve or prevent government enforcement.
  • Assists business clients in structuring transactions to allocate the risks and costs of addressing environmental exposures.
  • Has set up due diligence programs for lenders as well as for buyers and sellers of businesses and real property.


Chambers USA, Band 1 – Pennsylvania, Environment (2004–2019)

Best Lawyers®, Environmental Law (2020)

"Best Paper" Award Recipient, ABA’s Section of Environment, Energy and Resources’ (SEER) 46th Spring Conference (2017)

Who's Who in American Law

Awards Methodology (

The ‘outstanding’ Bonnie Allyn Barnett is widely recognized as one of the state's foremost Superfund experts. She also has considerable expertise in relation to regulatory compliance, permitting and litigation. According to a client: ‘She brings a really localized understanding but with the experience and credentials of a nationally renowned environmental attorney.’ Another client comments: ‘Her relationship and ability to negotiate with EPA and the different PRPs is unmatchable.’

Chambers USA (2019)

The 'very talented' Bonnie Barnett is considered a leading light in environmental matters, with peers hailing her 'outstanding' strengths in regulatory and litigation work. Her practice features niche skills in the remediation of contaminated sediment sites, alongside broader strengths in toxic tort cases, environmental liability disputes and permitting matters.

Chambers USA (2018)

The ‘brilliant’ Bonnie Allyn Barnett is a seasoned environmental practitioner, respected by peers and clients alike. She is noted for her litigation strengths, including toxic tort cases, and is also highly experienced in counseling clients on environmental regulations. Source reserve particular praise for her ‘excellent judgment.’

Chambers USA


Bar Admissions

  • New Jersey
  • Pennsylvania


  • Temple University Beasley School of Law, J.D., 1982, summa cum laude, Law Review
  • Temple University, B.A., 1979, summa cum laude

Court Admissions

  • U.S. Court of Appeals, Third Circuit
  • U.S. District Court, District of New Jersey
  • U.S. District Court, Eastern District of Pennsylvania
  • U.S. District Court, Middle District of Pennsylvania


  • Philadelphia Bar Association, Environmental Law Committee (Past Co-Chair)
  • Delaware Valley Inn of Court, Founder