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  • Writer's pictureDoug Kochanowski

What in the wide, wild, world is a Phase 1 Environmental Site Assessment?

Updated: Dec 1, 2020

First of all, in our profession, we refer to it as a Phase I ESA (use the Roman "I"). However, because I am hoping to educate the masses, and the masses that need educating more often search for Phase 1 ESA, I will use the incorrect but more often searched term of "Phase 1 ESA."

Simply put, a Phase 1 ESA is a visual and book study of a property to determine if it has been impacted by chemicals. There are three main components that are studied in a Phase 1 ESA that will lead us to our conclusions.

1) What is currently going on at the subject property.

This involves a visual inspection of the subject property. The use, handling, and disposal methods of hazardous materials are investigated. The subject property is inspected for signs of past and present uses that include signs of former Underground Storage Tanks (USTs), significant past chemical use, stained surfaces, and a host of other items. A long list of regulatory databases and environmental regulatory records are searched for evidence of proper hazardous materials management.

2) What is the nature of the past uses of the subject property.

The history of the subject property will be investigated dating back to when it was first developed or used for any purpose, such as agricultural uses. The goal is to identify past uses that may have used significant quantities of hazardous materials, petroleum products, or if landfilling activities have occurred on the subject property. Tools typically used to perform this research include the following: historical aerial photographs, historical topographic maps, historical city directories, Sanborn fire insurance maps, building permits, and environmental regulatory agency records.

3) What is going on at the adjacent and surrounding sites that may have impacted the subject property.

The same tools described above in 1) and 2) will be used to identify significant hazardous materials and petroleum product uses surrounding the subject property that may have had an impact. This will include a more detailed historical research on at least the immediately adjacent sites.


The Phase 1 ESA when properly performed will provide you with one of two possible conclusions:

1) There is no evidence that the subject property has been impacted by hazardous materials or petroleum products. All is well with this conclusion. You are now free to buy, sell, finance, lease, or develop your property without the requirement to perform any further environmental studies.

2) The subject property has, or may have been, impacted by hazardous materials and/or petroleum products. If you are unfortunate enough to get this conclusion, the Phase 1 ESA should include recommendations for subsurface testing. Recommendations will be made to test one or all of the following: soil, groundwater, and soil vapor. By following the recommendations of the Phase 1 ESA, you will then be performing a Phase 2 ESA, or correctly stated, a "Phase II ESA."

The Phase 2 ESA is a whole different topic discussed later. In general the Phase 2 ESA will give you one of three conclusions:

  1. There are no issues at the subject property.

  2. Testing was performed and the extent of subsurface contamination had not been defined. Therefore, more testing is required.

  3. The extent of contamination has been defined and cleanup options, if necessary, may be provided.


Good luck with your project and always feel free to call use at 800-567-7729 or email us with your questions to:

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