What The Records Don’t Always Reveal

As environmental professionals, we spend a significant amount of time reviewing historical records, aerial photographs, environmental databases, and regulatory files before ever setting foot on a property. These sources are critical components of the environmental due diligence process and often provide valuable insight into a site's history and potential environmental concerns. 

However, one lesson I continue to learn throughout my career is that properties are not always what they appear to be on paper. Sometimes, the most significant environmental concerns are only discovered during the site visit itself.

Real-World Example:

A few years ago, I completed a Phase I Environmental Site Assessment (ESA) on a property in “small-town Alberta” that initially appeared to present relatively low environmental risk.

The site had only been developed for approximately ten years and was reportedly utilized by a semi-truck transport company. The operations appeared straightforward: a few trucks and trailers were stored on-site, minor maintenance was performed, and the remainder of the property functioned as a typical commercial yard.

After reviewing the historical information, records, aerial photographs, and reported site activities, I did not anticipate finding any significant environmental concerns.

That assumption changed within minutes of arriving on-site.

While walking the rear portion of the property, I observed a used oil aboveground storage tank (AST). At first glance, it appeared unremarkable. However, upon closer inspection, I noticed a slow active leak originating from the base of the tank.

Surrounding the AST was a large, black-stained area of soil measuring approximately 15 feet by 20 feet. The vegetation within the affected area was completely dead, creating a stark contrast with the surrounding yard.

The visual evidence suggested that the release had been occurring for a very long time.

Subsequent environmental investigation confirmed exactly that. The tank had been slowly leaking used oil for nearly a decade, resulting in petroleum hydrocarbon contamination extending to depths greater than 10 feet below ground surface.

What initially appeared to be a relatively low-risk property ultimately required significant environmental investigation and remediation.

Why Site Reconnaissance Still Matters:

This experience reinforced something that every environmental professional eventually learns: not every environmental concern is documented in a file.

Historical records, environmental databases, and aerial photographs are invaluable tools, but they cannot identify every leak, spill, or improper storage practice that may have occurred on a property. Slow releases, in particular, can persist for years without ever being reported to regulators or appearing in environmental records.

That is why site reconnaissance remains one of the most important components of a Phase I ESA.

A thorough site visit provides an opportunity to identify visual indicators such as stained soils, distressed vegetation, improper chemical storage, unusual odours, stressed pavement, or evidence of historical releases that might otherwise go unnoticed.

For me, this project served as a valuable reminder that environmental due diligence is about more than reviewing records. Sometimes the most important finding of an entire assessment is one that was never documented anywhere at all.

Sam Siegl, C.tech, CESA
Sam is the founder and principal consultant of Nexus Environmental Services Ltd., based in Lethbridge, Alberta. With over a decade of dedicated experience in the environmental consulting industry, Sam specializes in Phase I, II, and III Environmental Site Assessments for commercial and industrial properties.
Sam can be reached at info@nexusenvironmental.ca