How NRDAR Differs from Remedial Actions under CERCLA

In addition to empowering natural resource trustees to pursue natural resource damage assessments (NRDA) NRDARs, the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) authorized two types of cleanups for releases of hazardous substances, short-term removal actions for those releases requiring immediate action, and longer-term remedial actions (RA) for those releases requiring substantial investigation and analysis. NRDARs are often performed at sites also undergoing RAs and it is therefore important to understand the similarities and differences between RAs and NRDARs. Even though the two processes have a similar overall structure and sometimes operate in parallel, their goals are remarkably different. While RAs are focused on current and prospective risk to human health and the environment, NRDARs are focused on returning injured natural resources to their pre-release condition.

The overall structure of RAs and NRDARs are quite similar. Remedial actions and NRDARs both use an iterative multi-step process to move from investigation and analysis to remedy (RA) or restoration (NRDAR). Both processes are designed to provide detailed information on site conditions to allow decision-makers to reach informed decisions on how to control risk to human health and the environment (RA) or to restore injured natural resource resources to baseline condition (NRDAR). Both rely on the liability provisions in Section 107 of CERCLA that make site owners, site operators, persons who arranged for the disposal or treatment of the hazardous substance, and transporters liable for response costs and damages to natural resources. Both processes often rely on robust and reliable modeling to guide decision-making. If litigation becomes necessary, CERCLA provides similar advantages to both remedial agencies and natural resource trustees if their actions are conducted consistent with the federally promulgated regulations for conducting RAs or NRDARs. (See 42 U.S.C. § 9607(f)(2)(C)) CERCLA grants trustees a rebuttable presumption in any judicial proceeding if the underlying NRDAR was conducted in accordance with 43 C.F.R. Part 11. CERCLA also makes responsible parties liable for costs of RAs if the RA was conducted in manner “not inconsistent” with the national contingency plan. (42 U.S.C. § 9607(a)(4)(A))

While the overall structure is similar, the design and intent of RAs and NRDARs are quite different. The National Contingency Plan describes the goals of the RA process as implementing remedies to “…eliminate, reduce, or control risks to human health and the environment” and EPA expects “… to use institutional controls such as water use and deed restrictions to supplement engineering controls as appropriate for short- and long-term management to prevent or limit exposure to hazardous substances, pollutants, or contaminants.” In contrast to risk reduction through engineering and institutional controls, the NRDAR regulations expect natural resource trustees to “…establish the amount of money to be sought in compensation for injuries to natural resources resulting from a discharge of oil or release of a hazardous substance. The measure of damages is the cost of restoration, rehabilitation, replacement, and/or acquisition of the equivalent of the injured natural resources to their baseline level of services.” Using similar tools remedial agencies and natural resource trustees answer distinctly different questions.

This pattern of similar structures but different goals is clear from a more detailed comparison of the steps in each process. The first milestone in the NRDAR process is the Preassessment Screen (PAS). The PAS is designed to use existing information in order to develop answers to questions regarding past, current, and future injuries to natural resources. The first milestone in the remedial process is to conduct a Preliminary Assessement/Site Inspection (PA/SI). The PA/SI is also designed to use existing information to determine whether the site poses a current and future risk to human health and the environment. Both the PAS and PA/SI may share the use of the same data and information but each uses the data to evaluate different questions to reach conclusions about risk or injury. (See 43 C.F.R. § 11.23(e))

The second major milestone in the NRDAR process is the preparation and implementation of the Assessment Plan. The Assessment Plan is designed to identify and quantify natural resource injuries and determine damages resulting from the natural resource injuries. Natural resource trustees should expect implementation of the Assessment Plan to provide information on past, current and future injuries to natural resources and the scale and scope of those injuries. This information is developed typically through extensive sampling and analysis, modeling, natural resource surveys, and other similarly reliable data gathering methodologies. The second major milestone in the remedial process is the Remedial Investigation/Feasibility Study (RI/FS). USEPA characterizes the RI/FS process as “…the mechanism for collecting data to characterize site conditions, determine the nature of the waste, assess risk to human health and the environment…” and “… the mechanism for development, screening, and detailed evaluation of alternative remedial actions.” (See USEPA Superfund discussion) The RI/FS process also uses robust data gathering and analysis tools similar to those used in the Assessment Plan phase of the NRDAR process, the RI/FS process seeks to answer questions about prospective risk instead of past, current, and future natural resource injury. Under both the RA and NRDAR process, following the RI/FS or Assessment Plan phase of the processes, litigation or settlement negotiations are often employed to resolve liability before remedial or restoration actions are implemented.

After basic remedial decisions are finalized, the next major milestone in the RA process is Remedial Design/Remedial Action (RD/RA). RD/RA includes the detailed designs and specifications for the remedial actions intended to eliminate, minimize, or control current and prospective risk to human health and the environment.  The RA process does not require the site to be returned to its pre-release conditions, only to ensure there are no unacceptable risks to human health or the environment from remaining contaminants.  The third major milestone in the NRDAR process has a similar overall structure to the RD/RA but has a significantly different purpose. The Post-Assessment Phase includes restoration planning and implementation. NRDAR restoration is not focused on controlling risk like the RA process, it is instead focused on returning ecosystem services to pre-release conditions by restoring or replacing lost natural resources. (See 43 CFR §§ 11.90 – 11.93)

The RA and NRDAR processes can often use the same data, and sometimes use similar tools to analyze relevant data, but each answer separate and distinct questions. A prime example of these similarities and differences can be seen in the models that each process uses to predict the impact of exposure to hazardous substances. If a remedial agency were establishing remedial goals for lead in residential soils to control for human health risk, it might use the Integrated Exposure Uptake and Biokinetic (IEUBK) model to determine site specific soil remediation levels. The IEUBK model uses interrelated inputs such as soil contaminant data, dietary lead intake, and drinking water data to estimate blood lead levels in children exposed to lead contaminated soil. A natural resource trustee may use soil contaminant data and plant or animal tissue data as inputs in the Habitat Equivalency Analysis model to develop estimates of the level of natural resource habitat necessary to replace the ecosystem services lost through injury from hazardous substance contamination.