Written by Bill Leedham, P. Geo., CESA, Down 2 Earth Environmental Services Inc.

In my last article, I discussed some of the common issues that may be encountered during the procurement, initiation and organization of Phase One Environmental Site Assessments (ESA). In this article, I will discuss ‘Procedural’ errors related to ESA Research that may occur while conducting a Phase One ESA.

Depending on the type of ESA (CSA, RSC, ASTM, Oil & Gas, etc.) there are specific research requirements for mandatory and/or optional data to be reviewed, historical time frame, and search distances – all of which can vary significantly with the respective regulatory regime. Failure to consider and incorporate the specific requirements can lead to regulatory rejection, project delays and unhappy stakeholders.

Regardless of the specific research requirements, the consultant must always gather sufficient information to provide an accurate, reliable and defensible assessment of actual and potential liabilities that may be present. Some of the more common deficiencies I encounter during peer review of Phase One ESA reports include:

Failure to research back to a property’s first developed use that could impact the environmental condition. I have seen reports that state there are no concerns since the site has been in residential use since a certain year; while completely missing historical industrial operations that predated the observed residential use by 50 years or more.

Failure to review all available historical documentation. I understand that some properties and locations may not have a lot of available historical documentation and the data is limited. It is frustrating however when no attempt is made to obtain and review all available resources such as Fire Insurance Plans, Street Directories, Freedom of Information requests, or subcontracted data such as an ERIS report. Whether this is due to budget constraints, lack of knowledge of available resources, or laziness (or a combination), it doesn’t matter – the necessary work needs to be done. For CSA-compliant reports I suggest the assessor review both the Mandatory and Optional data, and remember nil findings are still reportable findings.

Failure to recognize a relevant environmental concern. Given that the majority of environmental concerns at many sites are related to historical activities, it can be easy to miss a potential issue when there is little to no present-day evidence. This is even more difficult when compounded by an absence of historical data and lack of knowledgeable people to interview. An experienced assessor with good local knowledge may be able to uncover hidden nuggets of data, but getting a full picture of the site’s history may still be problematic. Missing ‘red-flag’ items like under ground storage tanks, hazardous waste generation or disposal, importation of contaminated fill, or the potential presence of hazardous materials like asbestos can lead to significant liabilities for both the stakeholders and consultant.

Failure to properly interpret the data. There can be a mountain of data to review, especially in highly developed areas with a lengthy industrial history. It’s not enough to simply list the data or refer to an appendix; the assessor must interpret the data in order to identify potential environmental concerns. For example, its not sufficient to review a couple years of Google Earth imagery, the consultant should review a series of detailed historical aerial photographs to note things such as ground disturbance, oil well development, areas of filling or dumping, historical tankage, etc. The assessor should look at and coordinate data from multiple information sources to better understand the implications of identified environmental concerns. Observations gathered from FIP, aerial photographs and street directories can inform and direct the site inspection and formulate interview topics. Review of all the data in conjunction with site observations, interviews, and regulatory inquiries should lead to, and support the report findings, conclusions and recommendations.


Bill Leedham, P. Geo., CESA, 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]