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Allocation Lessons for Superfund Sediment Sites: How Engaging with Environmental Experts Early Can Reduce Client Risk

Meredith Hayes and Richard Beach


  • Discusses the limitations of initial potentially responsible parties (PRPs) searches.
  • Looks at the advantages of developing a more thorough assessment of potential pathways of contribution, and/or an evidence-based estimate of the magnitude of likely contribution of contaminants.
Allocation Lessons for Superfund Sediment Sites: How Engaging with Environmental Experts Early Can Reduce Client Risk
Marli Miller via Getty Images

Superfund sites involving segments of rivers or other water bodies are known for contaminated sediments distributed over large areas, often encompassing many miles of a waterway. These sites are frequently located within older urban areas, and thus were subject to many potential sources of contamination over the past 100-plus years. The investigation and remediation of such sites is time consuming and costly. For example, it took more than 20 years of investigation of the Passaic River Superfund site to select an estimated $1.38 billion remedy––and that is for only a portion of the river. 

These costly cleanups are often funded by potentially responsible parties (PRPs) identified during PRP searches lead by the U.S. Environmental Protection Agency (EPA). A PRP includes any present or past owner of a hazardous waste site, a party who has arranged for disposal of waste at a site, or a party who has transported waste to a site. 42 U.S.C. § 9607(a). PRPs who pay for cleanup costs are allowed to seek contribution for those costs from other PRPs under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). 42 U.S.C. § 9613(f). Courts apportioning costs often do so by analyzing six equitable factors, referred to as “Gore” factors, although courts are not limited to using the Gore factors and may consider any appropriate equitable factor.

Identified PRPs are often encouraged to agree to a private allocation process to help manage their potential liabilities and to coordinate investigation and remediation activities with the EPA. This allocation process may use similar equitable factors as are considered by the courts. PRPs spend significant amounts of time and effort attempting to quantify source contributions from their own facilities to avoid being allocated unfair portions of the substantial costs involved in dealing with Superfund sediment sites, but these efforts are often expended after PRPs have already been named and incorporated into the allocation process. A proactive internal assessment of pathways and sources of contamination from a facility may reduce the possibility of being identified as a PRP, facilitate a reasonable and appropriate interim allocation yielding significant cost savings over the decades-long Superfund process, or aid in obtaining an early de minimis settlement. A de minimis settlement may be reached for a minor portion of the total response costs if the PRP is responsible for a minimal contribution (in amount and toxicity) of the hazardous substances or bought the site without knowledge of the contamination and did not cause or contribute to the contamination. 42 U.S.C. § 9622(g).

The Implications of Initial PRP Searches

PRPs are initially identified by the EPA (and its consultants), or by other PRPs, via broad desktop searches for information on potential sources of legacy contamination from facilities and historic operations. These searches may rely on publicly available references that generally can only provide limited and incomplete information. Search results are also often presented without complete context since minimal time is available to focus on the details of any one facility. Any facility that is currently using or has used hazardous materials and where a potential pathway for those hazardous substances to have entered the subject waterway exists is highly likely to be identified as a possible source of contamination, regardless of the magnitude of its contribution. The larger the facility operations and the more extensive its use of hazardous materials, the more likely the PRP will be identified and ultimately assigned a commensurately higher interim allocation. It is often assumed at this initial stage that a nexus exists between the release of hazardous substances at the facility and the response costs incurred, as required for CERCLA liability. 42 U.S.C. § 9607(a).

These initial PRP searches are useful in identifying potential sources of contamination, but their limited detail and conservative assumptions can imply much larger contributions by some PRPs than can ultimately be supported. However, once a PRP is identified as a contributor of contamination to a Superfund sediment site, there are few off-ramps from the typical 10- to 20-year allocation process, even if subsequent information suggests little to no contribution from the PRP’s facility. Interim allocations are developed at the onset of the allocation process and are based on this initial information. While a PRP’s final allocation may ultimately be reduced from the interim allocation, such a reduction is not easily achieved, nor is it a certainty.

A Proactive Approach

For certain PRPs, proactive steps taken prior to or early in the allocation process may reap substantial benefits as the allocation process proceeds. It can be advantageous to develop 1. a more thorough assessment of potential pathways of contribution, and/or 2. an evidence-based estimate of the magnitude of likely contribution of contaminants. PRPs identified as having pathways further removed from a Superfund sediment site (e.g., overland flow or process discharges that flowed through multiple pipes or ditches before entering the waterway) or who likely discharged a smaller mass of contaminants (e.g., stormwater discharges) are examples of good candidates for this type of proactive approach. Each PRP facility and Superfund site is unique; this technical strategy should be thoughtfully considered in the context of broader legal strategies.

Accurate Pathways Analysis

A more detailed understanding of the pathways (or lack thereof) for transporting contaminants to the waterway in question over the lifetime of the facility can be conducted through careful analysis. As an example, two facilities recently evaluated by the authors had been incorrectly asserted to have contributed contaminants via drainage ditches and stormwater pipes that flowed from the facilities to a Superfund Sediment Site. A methodical factual assessment of drainage flow directions was conducted through a review of multiple aerial photographs, topographic maps, the timeline of industrial development, site reconnaissance, and discussions with the local public works departments. In these cases, field inspections were critical to support flow pathways determined from historical aerial photographs. Invert elevations of ditches and stormwater pipes were obtained from the facilities to confirm the correct drainage pathways. Through these efforts, the nexus with the Superfund sediment site was “broken” for one of the facilities and resulted in a zero percent remedial allocation. For the second facility, the elimination of one migration pathway reduced its potential contaminant contribution—and thus the potential allocation—by an order of magnitude.

An Approach to Quantifying Contaminant Mass

The second element of the proactive approach is the development of a quantitative estimate of the likely contaminant mass that may have been released to the Superfund sediment site from the facility. This can be derived through an evaluation of each potential contaminant source and associated potential release points. Although measurements of contaminant concentrations in historic source materials (e.g., surface soils or stormwater flows) are often no longer available or incomplete, numeric estimates bounded by real-world values can be convincingly used if the logic for the bounding analyses and the references for the bounding assumptions are provided. The evaluation should incorporate an assessment of the uncertainty of the contaminant mass to further support the validity of the estimate. The potential contaminant mass from the facility can then be compared to the total contaminant mass in the waterway to normalize the facility’s contribution.

At a facility recently evaluated, the only potential nexus from the facility to the Superfund sediment site was via nonpoint source discharges from stormwater runoff. A hypothetical contaminant mass contribution was calculated through an evaluation of local drainage patterns, historic surface cover (e.g., impervious/asphalt, grass/soil), the potential for historical releases, historical soil sampling results, and estimated annual stormwater runoff. The results demonstrated that even if all the stormwater-entrained contaminants were transported from the facility to the Superfund sediment site, the resulting sediment concentrations would be over six orders of magnitude smaller than the median concentrations detected in the waterway.

Final Thoughts

The technical evaluations described in this article are appropriate for many facilities associated with Superfund sediment sites but may not apply to all facilities or PRPs. The approach to managing such liabilities is often unique and should be tailored to the specifics of each facility and site. The lesson learned from the allocation examples provided above is that earlier application of specialized technical evaluations may help certain parties not only limit their liabilities, but also potentially minimize or avoid some or all the costs associated with a lengthy allocation process.