Bonnie Allyn Barnett

Partner Philadelphia
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 was the chair of the Environment and Energy Group for more than twenty years and was elected to serve three terms as one of the managing partners of the firm.

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, 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 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.
  • 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 structure 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 (2004–2016)
"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 (

Bonnie has a highly diverse and respected practice which includes advising on sediment remediation issues and complex toxic tort litigation. Market sources say she is ‘exceptionally well connected and focused.’

Chambers USA

Chambers USA, Band 1 – Pennsylvania, Environment (2004–2016)


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