Michigan’s Updated MIRBCA Guidance: What Underground Storage Tank Owners and Operators Need to Know
Over the course of 2025, Michigan’s Department of Environment, Great Lakes, and Energy (EGLE) began releasing and implementing updated technical guidance known as Michigan Risk-Based Corrective Action (MIRBCA), a comprehensive framework governing how petroleum releases from underground storage tanks (USTs) must be investigated, assessed, and remediated under Part 213 of Michigan’s Natural Resources and Environmental Protection Act.
If you own or operate a gas station, fleet fueling facility, or any property with current or former USTs from which a petroleum release has originated, this guidance has significant implications for your potential cleanup obligations and liability, and having experienced legal counsel involved from the outset is a necessity. Here’s why:
The MIRBCA Process Is Complex and Consequential
MIRBCA establishes a three-tiered evaluation framework, each with different data requirements, assumptions, and corrective action implications:
- Tier 1 uses conservative, generic screening levels (RBSLs) similar to Part 201 residential/non-residential standards to simply determine whether concentrations pose any possible health risk.
- Tier 2 allows site-specific adjustments (e.g., fate and transport modeling, biodegradation rates, building-specific vapor intrusion parameters, etc.) to calculate higher, more realistic Site-Specific Target Levels (SSTLs).
- Tier 3 involves highly customized evaluations (with EGLE consultation recommended) for complex or high-value sites.
Selecting the appropriate tier is a crucial strategy decision that will impact how much you spend on investigation and remediation. Choosing the wrong approach, or failing to change approaches when appropriate, can mean the difference between thousands of dollars in unnecessary cleanup costs and a streamlined path to closure.
Liability Isn’t Always What It Seems
Determining who is legally responsible for corrective action under Part 213 is often far from straightforward. While the owners and operators of a property and/or the UST system at the time a release is discovered are generally liable to conduct corrective action, the statutory framework contains numerous exemptions, defenses, and carve-outs that can exempt certain parties from liability, or shift it elsewhere. For example, a person who purchased or began occupying a property may be liable for corrective action related to a past release if they fail to conduct and submit a Baseline Environmental Assessment (BEA) to EGLE within statutorily required timeframes (if no other exemption from liability exists), even if the release occurred long before the person purchased or began occupying the property. EGLE will not always clarify whether you qualify for an exemption, or it may dispute an exemption that should apply. Furthermore, there may be additional parties who are liable for the release that should be required to perform, or at least contribute to, the required corrective action. If you don’t know your rights or available defenses, you may begin incurring costs to perform corrective action you were never legally obligated to perform.
Understanding whether you are actually liable under Part 213, asserting your defenses if you are not, and avoiding unnecessary corrective action costs requires legal analysis at the earliest possible stage, before responding to any correspondence from EGLE. Once you begin conducting corrective action, it becomes significantly harder to recover those expenses. An experienced environmental attorney can evaluate the facts, identify applicable exemptions, and push back on improper liability assignments before you spend a dollar on unnecessary cleanup.
Contamination Doesn’t Always Stop at Your Property Lines
A petroleum plume often migrates underground, particularly in Michigan where groundwater is almost universally present. When contamination migrates beneath neighboring properties, the MIRBCA process requires you to characterize that contamination, notify affected property owners, and in many cases obtain their cooperation to complete your corrective action obligations, which can become very complicated very quickly. For example, you may need adjacent property owners to consent to:
- Access for sampling: installing and sampling groundwater monitoring wells, collecting soil borings and soil gas samples, and installing and sampling vapor pins in any structures on the property.
- Installing remediation equipment or engineering controls: air sparge and soil vapor extraction systems or installing direct contact barriers.
- Institutional controls: recording restrictive covenants that limit particular land uses, restrict groundwater use, require maintenance of direct contact barriers, and/or require any new structures to analyze and account for any potential soil vapor intrusion issues.
Neighbors who didn’t cause the contamination are often understandably reluctant to permit drilling on their land or agree to deed restrictions that could affect their property’s value. Obtaining their cooperation requires careful negotiation, clear communication about their rights and obligations, and, in many cases, competently drafted agreements. An experienced environmental attorney can navigate these sensitive conversations, structure access and other necessary agreements, and help resolve disputes and delays that can derail a corrective action timeline.
Selecting the Right Environmental Consultant is Critical
Not all environmental consultants are the same, and choosing the wrong one can be costly, both in money and time. An attorney who is familiar with the MIRBCA process and has experience working with qualified consultants can recommend an appropriate consultant for your situation, review the consultant’s proposed scope of work, and guide the corrective action strategy to ensure it aligns with your legal and financial interests.
Navigating Insurance and MUSTA Reimbursement
Having a knowledgeable environmental attorney to assist and oversee corrective action is particularly important when costs are being covered by a third-party, such as an insurer or the Michigan Underground Storage Tank Authority (MUSTA) Cleanup Fund. In those cases, the party funding the cleanup can influence corrective action strategy in ways that do not always align with your interests or goals.
Furthermore, with the potential costs associated with cleaning up a leaking UST site, ensuring that you follow all necessary steps to preserve any applicable insurance coverage and/or MUSTA eligibility is absolutely critical. Insurers routinely dispute coverage, question the reasonableness of expenses, and seek to pursue the cheapest corrective action strategy possible, regardless of whether that strategy is in your best interest. An attorney experienced in environmental insurance claims can review your policies, push back on unreasonable denials, and coordinate between your insurer and consultant to advocate for your position.
Similarly, MUSTA reimbursement is not automatic. Eligibility and reimbursement of costs depend on timely compliance with a number of requirements, including proper registration of the UST(s), timely reporting of the release, cost limits, and procedures for incurring and submitting eligible expenses. Failing to satisfy any one of these requirements can result in significantly reduced, or denied, reimbursement. Working with legal counsel before a release is reported can help ensure you are doing everything necessary to maintain MUSTA eligibility, rather than discovering a disqualifying deficiency after you’ve already incurred significant costs.
Protect Your Interests from Day One
At GGTM, we guide UST owners and operators through every phase of the MIRBCA process. We work hand-in-hand with environmental consultants to make sure their work supports your objectives, and we fight for every dollar of reimbursement and coverage you’re entitled to. The earlier we’re involved, the more options we can preserve for you (and the more costly mistakes we can help you avoid).
Contact us today if you’ve discovered a petroleum release, are purchasing property with a known, or suspected, current or former UST system, or have questions about your obligations under Michigan’s environmental cleanup laws.
This post is for informational purposes only and does not constitute legal advice.
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