Marshalling the Divisibility Defense to CERCLA Liability: Apportionment – Is the Harm Distinguishable?

Defining Harm to Establish a Divisibility Defense to Liability and Apportion Costs

Recording of a 90-minute CLE webinar with Q&A

Conducted on Tuesday, November 13, 2018

Recorded event now available

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Program Materials

This CLE webinar will discuss how recent court decisions have addressed divisibility in CERCLA litigation. The panel will guide environmental counsel on when and how the divisibility of harm defense is appropriate and tactics to overcome challenges in proving divisibility.


The U.S. Supreme Court’s decision in Burlington Northern & Santa Fe Railway Co. v. U.S. significantly changed the landscape for divisibility under CERCLA. However, there is still no bright-line test for determining divisibility, and several court decisions have shown that defining and distinguishing harm at a site may be difficult.

In decisions involving the Fox River in Wisconsin and the Upper Columbia River in Washington state, as well as opinions from courts in Rhode Island and South Carolina, judges and parties have wrestled with the threshold question for divisibility: is the harm “theoretically capable of apportionment”?

If a court answers this question with a “yes,” the party seeking to limit its liability may succeed; if no, that party may be jointly and severally liable and may have to bring contribution claims to shift responsibility to others under an equitable allocation approach. These and other opinions addressing the divisibility/apportionment divide continue to guide courts, litigants and pre-litigation parties as they attempt to settle or otherwise resolve responsibility at contaminated sites.

Listen as our authoritative panel examines the statutory language and what the Burlington Northern & Santa Fe Railway Co. v. U.S. decision and its progeny mean for divisibility. The panel will also review cases addressing this legal theory and offer practice pointers on which circumstances lend themselves to a divisibility defense, the main technical approaches available, and how to present it.



  1. Divisibility defense under CERCLA
    1. Statutory language
    2. What the BNSF decision means for divisibility
  2. Section 113 equitable contribution vs. apportionment
  3. Technical approaches to divisibility
  4. Lessons learned from recent decisions
  5. Best practices
    1. Circumstances lending themselves to a divisibility defense
    2. Presenting a divisibility defense


The panel will review these and other priority issues:

  • How are the federal courts applying the Burlington Northern decision in divisibility cases?
  • What factual circumstances lend themselves to a divisibility defense?
  • What steps can counsel take to overcome the challenging issues involved in proving divisibility?
  • When should parties consider divisibility as opposed to equitable allocation?


Hatfield, William
William S. Hatfield

Director, Environmental

Mr. Hatfield focuses his practice on environmental counseling in complex regulatory and litigation matters, strategic...  |  Read More

Love, Adam
Adam H. Love, Ph.D.

Vice President and Principal Scientist
Roux Associates

Dr. Love leads the firm’s Litigation Practice Group and provides forensic litigation support and expert witness...  |  Read More

Additional faculty
to be announced.

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