oil rig drilling in Alberta field

Plan Now, Success Later: A Strategic Approach for Efficient Oil & Gas Site Closure

October 6, 2025

By: GARY WINTHROP

In recent years, provincial jurisdictions across the Western Canadian Sedimentary Basin have been increasing the defined requirements for bringing inactive oil and gas sites to closure. British Columbia is the first western province to introduce prescribed timelines for decommissioning, assessing, and restoring sites after they become dormant. Other provinces are considering similar mechanisms – such as the new Liability Management Framework in Alberta – to improve and expedite reclamation efforts. 

Against this backdrop, companies holding inactive sites need to be increasingly aware of the liability risk that comes from inefficient and ineffective management of site portfolios. Risk from delay is most present at non-routine sites where complexities such as comingled contaminants, fractured bedrock, or extensive groundwater contamination, can require specialized expertise to address effectively. Inaction on the part of the liability holder, or ineffective action taken by contractors who lack expertise and experience working on complex sites, further decreases the likelihood that a site will meet regulatory closure requirements in a timely manner. Historically, the result has been a lot of rework, wasted time and money, and frustration on the part of private landowners about the lack of progress and repeated visits by contractors to their properties.

UAV training on site for Montrose Environmental team

Taking a strategic approach 

The solution begins with a comprehensive strategic plan that includes a process for screening sites within a portfolio to evaluate the degree of environmental risk, stakeholder challenges, and costs and timelines to achieve closure. By doing this up front, sites can be prioritized so multi-year execution plans, including financing requirements, can be developed and service providers can develop capacity for the skill sets and resources required. 

The degree of environmental risk can be ascertained through an understanding of the conceptual site model (CSM). The CSM is the understanding of the landscape and geological setting in which the site exists, the type and extent of contamination if any, and the potential for interaction of the contaminants with receptors: both environmental (i.e. ecosystem) and human health. This is a very important part of any site screening and strategic planning process, as sites with higher deemed environmental or human health risks ought to be given greater priority and have more emphasis to de-risk during the closure process. The complexity of the CSM also plays a crucial factor in how much effort and time will be required to advance a site through the various stages of the closure process to meet regulatory obligations. Identifying this complexity early in the process allows for work to be completed as efficiently and expeditiously as possible. 

Preparing for costs & roadblocks 

Costs and timelines to closure can be estimated from lived experience and/or financial and performance records from previously conducted assessment, remediation, and reclamation activities that were required to achieve restoration of a site and issuance of a regulatory instrument for closure. 

Stakeholder issues can impact costs and timelines to closure. Most landowners just want to see a fair and timely effort to restore their lands to equivalent capability or an agreed-upon alternate condition that will benefit their use. However, sometimes landowners or other stakeholders present challenges and roadblocks that impact the progression of a site to closure. Understanding which sites have these challenges and which sites do not is very useful when prioritizing work and sequencing activities.

Montrose team member groundwater drilling

A case for quality 

It’s worth noting that Phase 1 Environmental Site Assessments (ESA) are a mandatory regulatory requirement for closure of upstream oil and gas sites across Western Canada – typically the first step in the closure process during or after abandonment and decommissioning. Phase 1 ESAs form the basis for strategic planning, providing an accurate depiction of site development and production history, and offering a clear indication of areas of potential environmental concern and potential contaminants of concern. Unfortunately, within pockets of the oil and gas industry, the value of Phase 1 ESAs has become commoditized over recent decades. This often resulted in incomplete, incorrect, and difficult-to-consume information that is insufficient for making informed decisions on where to investigate potential contamination issues. Because these reports are the basis for effective strategic planning, it is critical that they are executed to a high standard of quality. Cutting corners at the Phase 1 ESA stage doesn’t pay off in the long run. 

Raising the bar on site closure 

As regulatory frameworks evolve and expectations for timely site closure grow sharper, the need for strategic, risk-based planning is clear. From the quality of early assessments to the prioritization of complex sites, organizations that approach closure proactively are better positioned to effectively manage their liabilities, build stakeholder confidence, and achieve regulatory compliance in an efficient manner. Elevating the standard of practice across the industry is not just about meeting requirements; it’s about strategies built on experience that deliver long-term environmental and community outcomes. 

Ready to get strategic in managing your inactive sites? Connect with us. 

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Gary Winthrop, P.Tech.
Vice President, Remediation & Reclamation
As Vice President, Remediation & Reclamation for Montrose’s Canadian consulting and engineering division, Gary leads a team of environmental professionals focused on assessment, remediation, and liability management for contaminated sites. With over 30 years of experience in environmental consulting, he has supported a range of projects, including delineating complex hydrocarbon plumes, evaluating the design and implementation of in-situ and ex-situ remediation technologies, and developing risk management alternatives and cost estimates for clients managing liabilities.