Remedial Investigationfeasibility StudyEdit
Remedial Investigation/Feasibility Study (RI/FS) is a two-stage framework used in the United States for addressing contaminated sites under federal environmental law. The RI characterizes the nature and extent of contamination and the potential risks to human health and the environment, while the FS develops and evaluates remedial options to address those risks. The outputs of the RI and FS feed into the Record of Decision (Record of Decision), the formal cleanup decision that guides subsequent design, construction, and long-term stewardship of a site. The process emphasizes data-driven decision making, cost considerations, and public involvement, and it operates within the broader regulatory landscape that includes CERCLA (the Comprehensive Environmental Response, Compensation, and Liability Act) and related requirements.
RI/FS is typically applied at sites subject to cleanup plans such as those overseen by federal agencies and state environmental programs. It often involves collaboration among site owners or responsible parties, federal and state authorities, and the public to ensure that remedies meet safety standards, are implementable, and provide long-term protection. The RI evaluates the current and future risks from contaminants, while the FS screens and analyzes possible remedies, balancing effectiveness, feasibility, and cost. The two steps together create a robust technical basis for deciding how a site should be cleaned up, including what kinds of remedies are appropriate and how they should be implemented.
Remedial Investigation
Purpose and scope
The Remedial Investigation aims to determine what contaminants are present, where they are located, how they move through the environment, and what risks they pose to people and ecosystems. It establishes the baseline conditions that any cleanup must address. This phase draws on data from soil, groundwater, air, sediment, and biological media, as well as information about potential exposure pathways and land-use scenarios.
Data collection and analysis
Key activities include developing a data quality objective framework, sampling programs, laboratory analyses, and spatial mapping of contamination. Analysts assess concentrations, frequency, and trends to define the extent of contamination and identify receptors at risk. The RI also considers ecological effects and potential cumulative exposures in nearby communities and habitats.
Risk assessment
A baseline risk assessment estimates current and future risks to human health and the environment in the absence of remedial action. It uses standard methods to evaluate carcinogenic and non-carcinogenic hazards, exposure scenarios, and receptor populations. The assessment informs the sensitivity of the site to different cleanup options and helps prioritize actions.
Deliverables
Typical RI outputs include a site description, maps of contamination plumes, a summary of contaminant fate and transport, and a risk characterization. These results feed directly into the subsequent Feasibility Study.
Feasibility Study
Purpose and scope
The Feasibility Study develops and evaluates remedial alternatives that could reduce or eliminate risks identified in the RI. The FS explores a range of options—from removal and containment to institutional controls and monitored natural attenuation—and presents each option with a conceptual design and cost estimate.
Alternatives development
EPA guidance commonly calls for creating a broad set of remedial approaches, then screening them to identify a focused set of viable alternatives. The screening considers practicality, potential impact on human health and the environment, and how well each option complies with regulatory requirements and community needs. Alternatives can include technology-based remedies (e.g., soil washing, groundwater extraction and treatment), containment strategies (e.g., barriers, capping), natural attenuation with monitoring, or combinations thereof, along with institutional controls to limit exposure or land use.
Evaluation criteria
Alternatives are evaluated against standard criteria, including: - Protectiveness of human health and the environment - Compliance with applicable or relevant and appropriate requirements (ARAR) - Long-term effectiveness and permanence - Reduction of toxicity, mobility, or volume of wastes - Implementability and constructability - Cost and cost-effectiveness - Community acceptance and social/economic considerations
Documentation and shortlisting
The FS results in a recommended remedy or a short list of preferred options, along with a detailed rationale, conceptual designs, and cost estimates. Analysts compare options against the evaluation criteria and present considerations for selection in the ROD.
Selection and Documentation
Record of Decision
The Record of Decision (ROD) documents the chosen remedy, explains why it was selected, and outlines the plan for design, construction, and operation. The ROD reflects technical findings from the RI and FS, as well as input from the public and regulatory agencies. It may specify performance goals, cleanup standards, and milestones for implementation.
Public involvement
Public participation is a core component of the RI/FS process. Communities, local stakeholders, and affected parties have opportunities to review technical documents, ask questions, and comment on proposed remedies. This engagement helps align technical choices with local needs and constraints and can influence final decisions.
Implementation sequence
Following the ROD, design and construction (where applicable) proceed, with ongoing monitoring and adjustments as long-term stewardship is required. The RI/FS framework thus serves as the planning basis for remediation, with subsequent steps ensuring that cleanup objectives are achieved over time.
Controversies and debates
Speed vs. thoroughness
Critics sometimes argue that the RI/FS process can be lengthy and costly, delaying cleanup actions. Proponents counter that rigorous data collection and systematic evaluation reduce the risk of selecting remedies that underperform or require costly changes later.
Risk-based versus conservative approaches
Debates often center on how risk is assessed and how conservative cleanup goals should be. Some emphasize precautionary, health-protective standards, while others advocate prioritizing efficiency and economic viability, arguing that excessive conservatism can hinder redevelopment and job creation.
Costs, benefits, and property impacts
Cost considerations are a central feature of the FS. Balancing upfront cleanup expenditures with long-term maintenance and monitoring costs is complex, and some stakeholders argue for streamlined procedures to accelerate redevelopment, while others warn that shortcuts could compromise safety or sustainability.
Equity and community outcomes
As with many environmental decisions, there are discussions about how RI/FS processes address vulnerable populations and environmental justice concerns. Proponents stress transparent engagement and fair consideration of local needs, while critics may argue that involvement is uneven or that remediations overlook long-term community benefits.