Department of Health Seal

TGM for the Implementation of the Hawai'i State Contingency Plan
Subsection 3.1


The first step of a systematic planning approach to site investigations is the effective scoping of available information and current site conditions in order to identify potential environmental problems at a property and develop an initial, Conceptual Site Model (CSM) (see Figure 3-1). This includes:

  • Review applicable regulations and guidance (see Sections 1 and 2);
  • Review site history and existing data;
  • Consult with stakeholders.

The information is used to develop a preliminary CSM (see Subsections 3.2.1 and 3.3), identify potential environmental problems and develop the site investigation approach, all of which are essential components of the Sampling and Analysis Plan (see Subsections 3.2.1 and 3.6).


Existing reports and other records can provide significant information about site characteristics and environmental issues. Previously prepared Phase I and Phase II environmental site assessments (ESAs) may be of significant value. Phase I ESAs are designed to identify potential environmental issues at a site based on field inspections, interviews, and a review of existing documentation. These reports are often required by legal and financial institutions to support property sales or other transactions (e.g., refinancing or facility expansions). Phase II ESAs are conducted to follow up on Phase I findings through the collection, analysis and evaluation of soil, groundwater, soil gas or other types of environmental samples (e.g., lead and asbestos testing of building material). Phase I reports are often confidential and may not be available in public files for the property. Phase II reports might also be confidential, especially if prepared by a perspective purchaser rather than the building owner or operator.

If a Phase I ESA is not available for the site, or if one is available but out-of-date, then a review of site records that follows the Standards for Conducting All Appropriate Inquiries 40 CFR Part 312 (also described in American Society of Testing and Materials [ASTM] E1527-13(ASTM, 2013) should be carried out. The types of records described by 40 CFR Part 312 include:

  • Physical setting sources (e.g., topographic maps and area-wide descriptions of geology, soil types, topography, and groundwater conditions);
  • Historical use sources (e.g., aerial photographs, Sanborn fire insurance maps, street directories, title information, and newspaper archives);
  • Federal, state, tribal and local government records or databases; and other environmental record sources as available (e.g., prior investigation reports, hazardous material and waste inventories, spill records, permits, etc.)

The detail and scope of the Phase I report depends in part on the needs of the requesting party as well as the experience of the preparer. The type and usefulness of information available for a property will vary. Information is more likely to be readily available for urban areas in comparison to rural areas, and for post-1970 time periods in comparison to earlier periods. Preparation of an adequate Phase I report is likely to require significantly more information than available in HEER Office public files for the property.

For example, site investigation scoping for identification of a suspected pesticide mixing area and other former agricultural operations at high risk for contamination might include the following elements:

  • Review of historical Sanborn fire insurance maps (see Figure 3-2) produced between late 1800s to 1970s, available at UH-Manoa library and other sources;
  • Review of historical aerial photos (for example, R.M. Towill Corp collection) (see Figure 3-3);
  • Review of archives for former sugar plantations (for example, UH-Manoa library and Hawaiʻi Agricultural Research Center);
  • Interviews with people who worked at the facility or are otherwise familiar with the area;
  • Inspection and photo documentation of identified, suspect sites.

Refer to TGM Section 9 for more information on pesticide mixing areas and former agricultural operations.

Figure 3-2. Portion of Sanborn Fire Insurance Map of Former Sugar Mill Operation Location of "Poison Mixing" area is identified, indicating potential pesticide contamination (e.g. arsenic). Sugarcane seed dipping vats generally are not indicated, which may have potential mercury or other fungicide contamination.

Figure 3-3. Historical Aerial Photo of Former Sugar Mill Operation Location of pesticide mixing area is identified as well as a sugarcane seed dipping vat. This is the same former sugar mill operation as shown in Figure 3-2.


Stakeholders are individuals or organizations who are affected by, who can affect, or who otherwise have interest, in the site (e.g., current and past owners, operators and employees; government agencies; nearby residents; developers; lenders; etc.). Stakeholders can be a valuable source of site information. For example, current or former employees can help document historical uses of the property, including locations of hazardous substance storage and disposal areas and point out other potentially important site features.

It is critical to consult with stakeholders early in the investigation scoping process to aid in an understanding of site issues. Early consultation with stakeholders, especially with the HEER Office, will help ensure that information collected during this stage of the environmental assessment process is sufficient to proceed to next steps. Avoidance of limitations on future use of the site should also be considered, for example by remediation of contaminated areas to meet unrestricted land use cleanup levels even though the property is currently used for commercial purposes (refer to HDOH, 2016).


The overall site investigation approach is broadly defined and progressively developed during the initial scoping stage of the assessment process. This can include a compilation of chemicals of potential concern, potential environmental hazards posed by the chemicals, the locations and types of media to be sampled and the general analyses to be performed.

Developing a general idea of the investigation approach facilitates systematic planning. Ultimately a more refined approach is developed and incorporated into the Sampling and Analysis Plan.