The current use of a commercial property does not necessarily represent its environmental history.
A property currently developed with an office building, retail center, warehouse, or multifamily complex may have previously been used for industrial manufacturing, petroleum storage, vehicle repair, agricultural operations, waste disposal, or other activities with potential environmental implications.
For this reason, historical research is a critical component of a Phase I Environmental Site Assessment.
Establishing the Historical Development of a Property
Historical research is used to establish how a property and its surrounding area developed over time.
Common sources include:
The objective is to identify changes in property use, development, occupancy, and surrounding land use that may be relevant to environmental conditions.
- Historical aerial photographs
- Historical topographic maps
- Sanborn fire insurance maps
- City directories
- Historical property records
- Previous environmental reports
- Regulatory records
- Property ownership records
- Available historical maps and photographs
Why Current Property Use Can Be Misleading
Consider a property currently occupied by a retail building.
A current site reconnaissance may show no obvious environmental concerns.
However, historical research may identify:
These historical activities may warrant additional evaluation even though no evidence of the former use remains visible at the site.
- A former gasoline station
- A machine shop
- A dry cleaner
- A manufacturing facility
- A vehicle repair operation
- Historical petroleum storage
- Former agricultural chemical use
Historical Research Should Include Adjoining Properties
Environmental risk is not limited to the subject property.
Historical uses of adjoining properties may also be relevant.
For example, a dry cleaner that operated immediately adjacent to the subject property for several decades could represent a potential source of chlorinated solvent contamination.
Similarly, a former gasoline station, industrial facility, or manufacturing operation located immediately upgradient of the subject property may warrant detailed evaluation.
The assessment therefore considers historical uses of the subject property as well as surrounding properties.
Interpreting Historical Information
Historical information should not be evaluated in isolation.
Suppose an aerial photograph shows an industrial structure on a property in 1975.
That information establishes historical use, but it does not by itself establish contamination.
Additional information should be considered, including:
Historical research therefore provides the foundation for environmental interpretation rather than serving simply as a chronology of property development.
- Nature of the historical operation
- Duration of operation
- Chemicals or petroleum products potentially associated with the operation
- Presence of tanks or waste storage
- Regulatory database listings
- Evidence of spills or releases
- Current redevelopment
- Available regulatory closure documentation
- Soil and groundwater conditions
Historical Research and REC Evaluation
The ultimate objective is to determine whether historical information contributes to the identification of a REC, CREC, HREC, or other environmental concern.
A former industrial use without evidence of a release may not necessarily constitute a REC.
Conversely, a relatively short-term historical use may become significant if documentation indicates that a release occurred.
Professional judgment is therefore essential when interpreting historical records.
At Greenearth, historical research is performed as a structured component of environmental due diligence, with emphasis on identifying historical uses that may affect current environmental conditions and transaction risk.