Phase I and Phase II Environmental Site Assessments (ESAs) are critical due diligence tools used to identify actual or potential environmental contamination on a land parcel, particularly for industrial or brownfield sites. While Phase I ESA involves historical and visual analysis, Phase II ESA includes physical sampling and lab testing. The following summarizes the types of contaminants typically identified during these assessments, organized by category:
1. Petroleum Hydrocarbons
- Detected in Phase II soil and groundwater samples, especially in sites with fuel storage, garages, or logistics yards.
- Includes benzene, toluene, ethylbenzene, and xylene (BTEX) compounds.
- Originates from underground storage tanks (USTs), fuel spills, or pipeline leaks.
- Persistent in soil and can migrate to groundwater, triggering cleanup mandates.
2. Heavy Metals
- Identified in both surface and subsurface soil—common in metal processing, foundries, and tanneries.
- Includes lead, arsenic, cadmium, chromium, zinc, and mercury.
- Often a result of industrial slag, metal dust, paint residues, or old electrical components.
- Long-term exposure risks for workers and the ecosystem require soil stabilization or removal.
3. Volatile Organic Compounds (VOCs)
- Typically revealed through vapor intrusion sampling or groundwater monitoring in Phase II.
- Includes trichloroethylene (TCE), perchloroethylene (PCE), carbon tetrachloride, and other solvents.
- Linked to dry cleaning, degreasing operations, or chemical blending industries.
- VOCs pose inhalation risks and require vapor mitigation systems or soil venting.
4. Polycyclic Aromatic Hydrocarbons (PAHs)
- Common at sites with historical coal tar, asphalt, or combustion activity.
- Includes naphthalene, anthracene, and benzo[a]pyrene.
- Identified in surface and subsurface soil, particularly near incineration or coal storage areas.
- Often necessitates partial excavation or capping of the contaminated layers.
5. Asbestos, PCBs, and Other Legacy Materials
- Phase I may reveal the presence through building material review or utility inspection.
- Asbestos-containing materials (ACMs) are found in roofing, insulation, or tiles of older structures.
- Polychlorinated biphenyls (PCBs) may exist in old transformers, capacitors, or fluorescent lighting.
- Require regulated removal and disposal under hazardous waste laws.
