Written by Bill Leedham, P. Geo., CESA, Associated Environmental Site Assessors of Canada

Over the last few articles, I have discussed some of the structural and procedural errors commonly encountered when conducting a Phase One Environmental Site Assessment (ESA). In this article, I continue with the examination of problems with ESA interviews and site inspections.

The Interview

Interviews are an important facet of ESA work that in my opinion, are often overlooked and underperformed. According to Canadian Standards Association (CSA) Standard Z768-01, the purpose of the interview is to corroborate or augment the information gathered in the records review, or the site visit; or to provide information useful to planning the Site visit.

The selection of interviewees by the assessor is just as important as the content of the interviews – and the assessor should document their rationale for selection of interviewees. Interviewing the client at the start of the project can identify the involved stakeholders and determine their objectives; since the client may be a completely different entity than the property owner and the tenants.

The assessor also needs to interview property owner(s), tenants, past owners and others with knowledge of the property and its historical development. CSA also stipulates that the assessor make a reasonable attempt to interview at least one of several types of government agencies or officials, especially in cases where there may be a lack of knowledgeable site contacts.

The most deficient interview process I have encountered in peer review comprised a single interview with only the owner/vendor’s real estate agent. Of course all the interview answers consisted of “Not that I am aware of….” This can be difficult when there are conflicting accounts, faulty memories or in some cases, outright bias or deceit.

The assessor must ensure sufficient interviews are conducted with knowledgeable individuals so that the observations and findings are fully supported, potential bias is ruled out, and conclusions are justifiable.

The Site Inspection

The site inspection (site reconnaissance) is an integral and vital part of the ESA process. The assessor must view all areas of the property that are safely accessible.

There may be difficulties with denied or restricted access, limiting factors such as heavy snow cover, possible time limits for the inspection, or conflicts with the availability of knowledgeable site staff. These difficulties can be further compounded since many of the potential environmental concerns that we need to identify are historical and may no longer be present at the property. This necessitates a search for hidden clues to past problems – such as evidence of former fuel storage (vent/fill pipes, records of old boilers); importation of suspect fill (unusual grading, ground disturbance); or the presence of Special Attention Items such as asbestos or lead paint.

It is helpful to have a knowledgeable staff member accompany the assessor, not just for information about the site and activities, but also from a safety perspective if there are any potential hazards at the Site. The assessor should plan the timing, scope and coverage of their site visit in advance. It’s helpful to send a list of required documents, personnel and areas for inspection to the facility in advance of the inspection so that site staff can prepare for the visit.

One must also consider any health and safety requirements – this can require site specific Personal Protective Equipment (PPE) and/or safety training/orientation.

Lastly, the extent of the inspection and time required for completion can vary significantly with the size, age, complexity and location of the subject property – and these variables must be considered in the budget, planning and health and safety aspects for all ESA site inspections.In future blog(s) I will cover some of pitfalls that an assessor may run into with interpretation of collected data and Phase One ESA reporting.


Bill Leedham, P. Geo., CESA
Bill is the Head Instructor and Course Developer for the Associated Environmental Site Assessors of Canada (
www.aesac.ca); and the founder and President of Down 2 Earth Environmental Services Inc. You can contact Bill at [email protected].