5.3. Clearance Goals and Options

Selecting clearance goals should be based on a flexible approach where a variety of dose- and/or risk- based exposure guidelines (e.g., advisory levels, clearance goals) from federal, state, or other sources (e.g., national and international advisory organizations) are reviewed in the context of the incident at hand. Exposure guidelines of higher or lower concentration may be appropriate depending on the site- specific circumstances or in order to balance other relevant factors such as technical feasibility.

A flexible process in which numerous factors are considered to achieve an end result that balances local needs and desires, health risks, costs, technical feasibility, and other factors may be warranted. The general process outlined in this document provides decision-makers with input from technical experts and stakeholder representatives, as well as providing an opportunity for public comment. The extent and complexity of the process for an actual incident should be tailored to the characteristics and needs of a given incident.

Activities may include quantitative and qualitative assessments applied at each stage of site restoration decision-making, from evaluating remediation options through implementing the chosen remediation alternative. Evaluating and prioritizing remediation options following an incident should balance relevant factors, including:

• Types of contamination (e.g., CWA or TIC)
• Other hazards present
• Risk-based human health exposure guidelines
• Areas affected (e.g., size, location relative to population)
• Projected land use
• Preservation or destruction of places of historical, national, or regional significance
• Actions already taken and decisions made during crisis management to protect public health and the environment
• Public welfare
• Ecological risks
• Costs and available resources to implement and maintain remedial options
• Potential adverse impacts of remedial options to human health, environment, economy, etc.
• Technical feasibility of remediation options
• Long-term effectiveness
• Wastes generated and disposal options and costs
• Timeliness
• Public acceptability, including local cultural sensitivities
• Economic effects (e.g., tourism, business, and industry)
• Environmental equity and justice

A flexible process provides an opportunity for decision-makers to involve stakeholders and build public confidence in the decision-making process.

5.3.1. STAKEHOLDER CONCERNS

Future use of site/population of concern. Appropriate mechanisms to coordinate with stakeholders (such as property owners and SLTT government officials as well as representatives of business and community groups) should be established as part of the consequence management planning process. One of the initial communications with stakeholders should be to determine the types of activities and persons who are anticipated to occupy or use the contaminated area/facilities. Vulnerable populations of concern, to include individuals with disabilities and others with access and functional needs, should be identified.

Environmental justice considerations should be considered whether there is a disproportionate impact on communities of color, low-income communities, and other underserved or historically marginalized communities. Discussion should include consideration of potential alternative land/facility uses or institutional controls that could be selected to minimize exposure.

Types of health effects. The types of health effects that may be caused by exposure to the chemical of concern may be perceived differently by the various populations at risk. Acute or immediately noticeable symptoms will typically be easier to detect and describe. Those effects that are more pronounced or severe (such as difficulty breathing) will likely be of greater immediate concern. Effects that occur only after long-term exposures and/or that take years to develop (such as cancer) may be less certain but may result in significant fear among those at risk.

5.3.2. FEASIBILITY ISSUES

Chemical Detection. Clearance goals should be evaluated in context with the ability to verify residual chemical contamination using one or more analytical methods. In order for chemical analysis to be able to confirm that an area has been sufficiently decontaminated, the detection limit of the analytical method should be lower than or equal to the clearance goal. In addition to the analysis method to detect a chemical at a sufficiently low quantitation level is the issue of sampling efficiency. Sampling efficiency will vary according to chemical, surface type and environmental media. Collected samples require analyses in specialized laboratories. Only select laboratories will have the capability to analyze for all chemicals of concern in various matrix types, limiting the capacity to analyze samples, and wide-area response may overwhelm laboratory resources. The EPA has developed a Best Practices to Minimize Laboratory Resources for Waste Characterization During a Wide-Area Release of Chemical Warfare Agents. This

document contains information that may be useful for labs to use during such an incident.⁶⁵ Risk management options (e.g., institutional controls) may need to be considered if it is not possible to verify a successful decontamination analytically.

Remediation Options. The remediation options selected should provide an adequate mechanism for cleaning up in an effective, timely, cost effective manner. Factors to consider when selecting remediation options are summarized below:

• Chemical Parameters. The first consideration is whether the cleanup approach is feasible and effective for the chemical of concern. This will generally be supported with some data or knowledge of the chemical structure and other parameters. However, the form and amount of the chemical present, temperature/humidity, and other environmental conditions and chemical parameters may have an impact on cleanup effectiveness. For example, monitored natural attenuation may be a desired approach for highly volatile compounds. But if a large amount of liquid agent is present, the temperature is quite low or the chemical contaminant is persistent, other, more aggressive techniques may be desired. Engineering feasibility studies may be needed to ensure remediation options can meet desired results.

• Materials and Surfaces Characteristics. Some environmental materials and surfaces, including organic and polymeric materials, are more difficult to address because they act as sinks and require specific remediation approaches.

• Impacts on Safety and the Environment. Certain decontamination methods may be extremely dangerous to apply or may cause extreme damage to properties/facilities, thus rendering them inoperable or otherwise requiring additional restorative operations. When possible, less toxic and destructive methods should be evaluated.

5.3.3. UNCERTAINTIES/CONFIDENCE ISSUES

Availability/confidence in clearance goal. Despite the availability of numerous quantitatively derived human toxicity and health-based exposure guidelines for certain chemicals and certain types of environmental materials and surfaces (Appendix A), there may not be an existing exposure guideline appropriate for a given chemical release event. Below are two examples of methods that could be used in such situations:

• Reviewing available toxicity data (animal studies, human studies, anecdotal information) to determine if a human exposure value could be estimated using the same procedures and principles used to develop the exposure guidelines described in Appendix A

• Using structural modeling (e.g., QSAR) or surrogate/relative potency chemical toxicity information to estimate toxicity

The use of approaches such as those mentioned here may increase the uncertainty and decrease confidence in the clearance goal.

Interpretation and application of toxicity and exposure for clearance goal derivation. As previously discussed in Section 5.2, many of the acute and short-term exposure guidelines described in Appendix A are prescribed for use only during initial response decisions, such as evacuation/sheltering-in-place or emergency drinking water guidance. These acute and short-term values will likely not be appropriate as final clearance goals. Ideally, the full range of exposure guidelines and the underlying basis/assumption should be evaluated for appropriateness to the phase of the remediation process under consideration (Appendix A).

Decontamination approach effectiveness. Upon evaluation of all factors relevant to the circumstances of the site and scenario at hand, there may be substantial confidence that the decontamination process will be very effective. The remediation approach should be based on a balance of the desired future use of the site and associated cleanup decisions (upper bound as well as any more protective lower-level goals), the feasibility of implementing the cleanup operation, and the resources needed as well as any containment/protective barriers to minimize adverse environmental and/or health effects that might result from the remediation operation itself (e.g., run off of wastewater containing decontamination solutions). A pilot study may be helpful in improving confidence in a selected remediation approach.

5.3.4. TIME/RESOURCES ISSUES

Extent of contamination. The magnitude of the affected area may be so large and contamination so vast that uniform site clearance goals may not be feasible. In those instances, risk management decisions that mitigate risk but permit limited access may be warranted.

Critical infrastructures/items. If structures or facilities (such as power plants, water treatment plants, hospitals, or key government operational centers) that provide critical services to the local populations or to state or national operations are shut down due to potential or known contamination, these areas may need expedited cleanup and clearance. Stakeholder and other pressures may also identify other areas, facilities, or items of special importance.

Economic impacts of cleanup options. Similar to the need to clear areas that provide critical infrastructure service, certain business operations (e.g., national and international financial centers) may also need to be considered when choosing the remediation approach and associated objectives. The overall cost of operations versus those associated with other options must be considered. There are often multiple cleanup methods to achieve the same clearance goals. For example, monitored natural attenuation will result in minimal direct costs but may require more time or sampling, which can delay reopening facilities and possibly increase indirect (economic) cost. More aggressive options may incur higher direct costs but are likely to result in shorter time to reoccupy and limited post-decontamination monitoring.

5.3.5. WASTE MANAGEMENT ISSUES

Collecting decontamination solution and removing contaminated material or items destroyed by the decontamination process can be resource and cost intensive. With less well-known chemicals (e.g., CWAs, exotic TICs), it may be difficult to find an appropriately permitted, suitable, and willing disposal facility.⁶⁶ In some cases, waivers to established waste management, treatment, and transport requirements may be needed.

The issue of waste management for a large-scale, highly toxic, hazardous chemical release response is a complex issue. One of EPA’s principal roles is to provide technical support to FSLTT authorities, industry, and other stakeholders on waste management decisions before, during, and after a large-scale chemical contamination incident occurs. Reponses to large-scale chemical releases involve waste management issues and decisions, which can significantly affect the cost and timeline of the response to and recovery from the incident. For example, terrorist events can result in large amounts of contaminated materials and debris, large-scale natural disasters can generate large quantities of mixed debris, and animal disease outbreaks may result in the need to treat and/or dispose of large volumes of contaminated carcasses. Pre-incident waste management planning is an important aspect of being prepared and can reduce the time and cost of response and recovery from a chemical incident.⁶⁷ Therefore, it is important to incorporate planning and stakeholder participation into the waste management decision-making process in large-scale chemical contamination incidents as early as possible. To address difficult waste management issues, EPA’s Incident Management Handbook recommends the use of a waste management specialist, development of a waste management plan, and the use of a technical working group to tackle difficult waste management decisions. Advice and planning tools for chemical contamination incident responses can be found at the EPA waste management website.⁶⁸ EPA conducts preparedness planning operations to develop strategies and support documents for waste management when dealing with disposal of debris or other wastes contaminated with CWAs. EPA also develops a number of supporting tools and/or documents that may assist in waste disposal, including the I-WASTE Decision Support Tool (I-WASTE DST). The I-WASTE DST is used to estimate types and amounts of waste streams for certain facilities and provides a national listing of treatment/disposal facilities to assist during the planning and preparedness activities.

5.3.6. OTHER CONFOUNDING FACTORS

Human Exposure Guidelines. The lack of comprehensive human exposure guidelines and toxicity values for inhalation, dermal, or ingestion routes of exposure that are available for civilian sector clearance may confound the clearance process.

Breakdown products and collateral hazards. Even if the hazardous chemical itself does not persist, persistent/toxic breakdown products may remain as byproducts or other contaminants and may be released by explosions or during decontamination and demolition operations (collateral hazards). Such breakdown products and collateral hazards may be of lesser concern initially, but early consideration of these potential longer-term issues will assist in the process of determining cleanup options and clearance sampling. For example, some breakdown products can be avoided through appropriate selection of decontamination technology.