Department of Health Seal

TGM for the Implementation of the Hawai'i State Contingency Plan
Section 19.1
SITE CLOSURE SCOPING

19.1 Site Closure Scoping

Site closure scoping is an important step that includes evaluating future land uses and determining site closure implications of the selected remedy. Site closure scoping can be part of the removal action work plan/removal action alternatives analysis (see Section 14), or the remedial alternatives analysis/response action memorandum (see Section 16).

19.1.1 Evaluation of Future Land Use

Planning or knowledge regarding future land use is crucial to evaluating site closure decisions. Evaluating future land use typically involves reviewing available records, determining current land use, inspecting the site and surrounding area, and discussing future uses with local government officials, current and future property owners, and the community. Further information about evaluating future land use is available from the United States Environmental Protection Agency (USEPA, 2001d).

19.1.2 Remedy Selection and Site Closure Implications

During the remedial alternatives analysis (for remedial response actions), remedies undergo a comparative analysis that focuses on the performance of each remedial alternative against three criteria: (1) Effectiveness, (2) Implementability, and (3) Cost (see Section 16). In addition, all potential remedial alternatives, except the required No Action alternative, must meet the threshold criterion of being protective of human health and the environment.

Considering the post-closure implications of each remedial option is essential to properly evaluating long-term effectiveness, implementability, and cost. Several issues must be considered to attain a site closure that is acceptable for the planned future site use and to the stakeholders involved.

Issues to consider during remedy selection and evaluation of post-closure implications include:

  • Will the remedy restrict future land (or groundwater) use at the site?
  • Will stakeholders concur with the land use restrictions?
  • Will current and future property owners commit to implementing and maintaining the land use restrictions?
  • What practices and safeguards will need to be implemented and maintained to ensure safe use of the property?
  • Will the remedy compromise the architectural integrity of on-site structures?
  • How will land use restrictions affect the property value? For example, will financial institutions be wary of loaning funds to prospective purchasers in future real estate transactions if contaminated soil and/or groundwater remains on site?
  • What will be the long-term costs of institutional and engineering controls associated with managing contamination on site?
  • What long-term effectiveness can be expected of the institutional and engineering controls? For example, will institutional controls (e.g., an environmental covenant) and engineering controls (e.g., a visible marker or boundary layer) be effective in preventing future site occupants from digging into contaminated soil or groundwater?
  • What potential legal liabilities may be caused by managing contaminated soil or groundwater on site? Are landowners and other stakeholders willing to accept those liabilities?
  • Will an exemption of liability for prospective purchasers granted for voluntary response actions (if the cleanup is completed under the VRP) increase the value of the property? Will an increase in value outweigh any additional costs associated with participating in the VRP?

Containment Remedies

Remedies that leave hazardous substances remaining on site as a permanent solution are known as containment remedies, because the hazardous substances are not removed or destroyed, but only contained. Containment remedies prevent hazardous substances from impacting public health or the environment only as long as they are maintained. Use of containment remedies will necessitate land use restrictions at the site.

If a containment remedy is being evaluated, the potential for it to fail over the long-term should be closely assessed. Several examples of potential remedy failures include:

  • Failing to continue operation and maintenance of an active engineering control, such as an active vapor mitigation system.
  • Failing to implement, maintain, and report on required monitoring.
  • Failing to notify construction workers, tenants, etc. of use restrictions.
  • Failing to prevent forbidden land uses, such as allowing residential use of land or soil cleaned up only to commercial/industrial Environmental Action Levels (EALs).
  • Actively breaching a passive engineering control, such as digging through a protective soil layer, barrier, or visible marker into contaminated soil.
  • Failing to incorporate protective systems designed to prevent exposure, such as constructing a new building on the site without the necessary vapor mitigation measures.
  • Sale of the property without appropriate disclosures

Containment can be the least expensive remedy in terms of initial capital costs. However, when all of the associated costs are included (such as institutional control development, preparation and implementation of an Environmental Hazard Management Plan (EHMP), long-term monitoring costs, long-term operation of engineering controls, future incremental costs of managing contaminated materials, depreciation of land value, and maintenance costs), containment remedies typically have comparable costs to treatment remedies or removal actions. These long-term costs should be included in the Removal or Remedial Alternatives Analyses. The potential consequences of containment remedy selection include:

  • Continued reporting
  • Continued cost for monitoring and operation and maintenance
  • May be ordered to take action under Hawai‘i Revised Statutes (HRS), Chapter 128D (HRS 128D) (the state government)
  • May be ordered to take action under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) (the federal government)
  • Vulnerable to third-party torts if people claim harm
  • Continued listing on state cleanup site lists
  • Continued visibility to the community as a cleanup site with existing contamination
  • Site flagged by Phase I Environmental Site Assessments
  • Site listed as a liability on corporate balance sheets under Sarbanes-Oxley reporting
  • Site property value decreased
  • Less attractive to developers due to environmental protections needed for construction
  • Engineering controls make future construction more difficult (e.g., concrete caps)
  • Residual contamination may subject future construction workers to exposure hazards

In summary, remedial options must be thoroughly evaluated to determine the post-closure implications of each. Selection of a site closure option acceptable to the stakeholders involved will expedite the process and avoid costly and unnecessary delays.