Comprehensive RI/FS Strategy:
The American Thermostat Site
A multi-decade legacy transition from 1954-1985 manufacturing operations to modern, data-driven remediation. This brief outlines the 2024 scope for source isolation, vertical DNAPL profiling, and infrastructure risk mitigation.
Total Managed Soil
65,000Tons
Waterline Extension
3.5Miles
Groundwater Treated
115MGal
VOC Mass Removal
1.75Tons
1.0 Executive Framework
The American Thermostat Superfund site is entering a critical data-intensive phase under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Following the 2024 Five-Year Review, the EPA has determined that while initial remedies (OU1/OU2) provided protection, residual high-concentration source areas continue to feed the groundwater plume.
Regulatory Directive: CERCLA § 121
Requires remedial actions to be protective of human health and the environment, be cost-effective, and utilize permanent solutions and alternative treatment technologies to the maximum extent practicable. The 2024 Work Plan is drafted to meet these statutory mandates.
The 2024 RI/FS Work Plan (Task Order W912DQ23F3020) provides the blueprint for investigating these remaining source zones. The primary goal is to determine if mass remains beneath the former assembly building or within the deep bedrock fractures that could be efficiently remediated to accelerate site closure.
2.0 Operational History & Source Characterization
From 1954 to 1985, operations involved the assembly of thermostats for small appliances. Manufacturing processes utilized vast quantities of organic solvents for degreasing. Historical mismanagement led to the disposal of waste solvents—primarily PCE and TCE—into abandoned septic systems and directly onto the parking lot.
Primary COC: PCE
Tetrachloroethene: A dense non-aqueous phase liquid (DNAPL) with low water solubility and high persistence in deep bedrock.
Secondary COC: TCE
Trichloroethene: A volatile organic compound often resulting from the degradation of PCE, highly mobile in groundwater.
Technical Term: DNAPL
Dense Non-Aqueous Phase Liquid: Liquids that are heavier than water and do not dissolve easily. At American Thermostat, these chemicals "sink" through the aquifer until they hit the bedrock contact, often pooling in "depressions" or migrating through fractures.
3.0 2024 Remedial Investigation (RI) Technical Scope
The current scope, managed by Tetra Tech under USACE oversight, utilizes a Triad approach—combining systematic planning, dynamic work strategies, and real-time measurement to optimize data collection.
Sub-Slab Soil & Vapor Profiling
The contractor will perform asbestos abatement in the former plant building (due to legacy floor tiles) to allow for sub-slab drilling. This will confirm if a "secondary source" exists directly beneath the manufacturing floor that was missed during previous soil removals.
High-Resolution Vertical Profiling (HRVP)
Deep bedrock borings (82 total planned) will utilize discrete-interval sampling to map the vertical distribution of the plume. This allows the team to identify exactly which bedrock fractures are carrying the most mass.
Passive Diffusion Bag (PDB) Sampling
Utilization of PDB samplers in existing monitoring wells to gather long-term VOC concentration data without the turbidity artifacts often introduced by traditional purge sampling.
4.0 Feasibility Study (FS) Optimization
Data from the RI will feed the FS, which evaluates remedial alternatives against the Nine NCP Criteria. The objective is to move beyond the current "Pump and Treat" (P&T) system, which has reached an asymptote in mass removal efficiency.
Potential Remedial Technologies Under Review
- In-Situ Chemical Oxidation (ISCO): Injecting oxidants to destroy VOCs in-place.
- In-Situ Thermal Treatment (ISTT): Heating the subsurface to vaporize DNAPL.
- Enhanced Bioremediation: Stimulating native bacteria to "eat" the solvents.
- Monitored Natural Attenuation (MNA): For low-concentration distal plume areas.
Technical Glossary
Applicable or Relevant and Appropriate Requirements (Regulatory standards).
National Priorities List (EPA's list of most hazardous sites).
Record of Decision (Legal document explaining the chosen remedy).
Maximum Contaminant Level (Legal threshold for drinking water).
U.S. Army Corps of Engineers (Technical oversight body).
Capital & Contracts
Estimated RI/FS Cost
$2,400,000+
Cumulative Site Spend
$26.1M (Historical Total)
Funding Stream
Bipartisan Infrastructure Law (BIL) / Federal Superfund
Community Impact
The 3.5-mile waterline loop (Phase 2) will serve 61 residents, providing permanent risk-transfer and decoupling residential safety from site groundwater quality.
View Community Update5.0 Hydrogeological Conceptual Site Model (CSM)
The Site lies within the Hamilton Group, characterized by siltstone and shale. Bedrock is encountered at depths of 28–30 feet bgs. Groundwater flow is primarily controlled by bedrock fracture orientation, migrating toward the Catskill Creek valley to the north.
Overburden Characteristics
Glacially-derived soils and sediments overlaying the bedrock. Groundwater in the overburden is found at depths of 5 to 8 feet.
Investigation Objectives (DQOs)
- Delineate lateral and vertical extent of VOCs.
- Quantify mass flux through fractured bedrock.
- Evaluate the stability of the plume vs. historical data.
- Assess sub-slab vapor intrusion (VI) risks for on-site reuse.