Each fall, facilities across Michigan are required to complete the Annual Equipment Inventory Review (EIR) in MiEnviro Portal. While it may not get as much attention as the Annual Emissions Report (AER), the EIR plays a critical behind-the-scenes role in ensuring a smooth and accurate reporting season.
The EIR becomes available on September 1st and is due by November 1st. This review ensures that all emission units, processes, and release points are properly captured in MiEnviro Portal ahead of the AER reporting window, which opens in early January and is due by March 15th.
For anyone responsible for environmental compliance, completing the EIR accurately and on time is an essential step toward avoiding unnecessary delays when emissions reporting begins.
What Is the EIR Form and Why Does It Matter?
The EIR is an annual check-in that confirms your facility’s equipment inventory is current. It allows you to:
- Verify that your emission units and stacks are accurately listed in MiEnviro Portal
- Update any shutdown, modified, or new equipment
- Ensure the system is ready to generate your Annual Emissions Report come January
Think of the EIR as the setup phase before the real reporting begins. The EIR updates your facility’s Master Facility Inventory (MFI), which stores the emission units, processes, release points, control devices, and control pathways used to populate the Annual Emissions Report. If equipment data is outdated or incorrect, it can cause errors or omissions in your emissions report, resulting in unnecessary headaches.
Which Emission Units and Stacks Must Be Reported?
Not every emission unit at your site will need to be included in the Annual Equipment Inventory Review or Annual Emissions Report, but knowing what does is key. Emission units should be included if:
- They are listed in your Permit to Install, Opt-Out Permit, or Renewable Operating Permit (ROP)
- They are not exempt under Michigan’s Rule 201, or
- They are subject to a federal standard (e.g., NSPS or MACT), or
- They emit more than 10% of the significance thresholds in Rule 119(e), see Significant Levels Table below:
Significant Levels
| Pollutant | Significant Level (Rule 119(e))
tons/year | 10% of Significant Level
tons/year |
| Carbon Monoxide (CO) | 100 | 10 |
| Nitrogen oxides (NO2) | 40 | 4 |
| Sulfur oxide (SO2) | 40 | 4 |
| Particulate matter (PM) | 25 | 2.5 |
| Particulate matter (PM2.5) | 10 | 1 |
| PM-10 | 15 | 1.5 |
| Volatile organic compounds (VOC) | 40 | 4 |
| Lead (Pb) | 0.6 | 0.06 |
Even Rule 201-exempt units may need to be included if they meet certain thresholds or regulatory requirements. To help facilities make that determination, the Michigan Department of Environment, Great Lakes, and Energy (EGLE) developed a structured five-step process based on permit status, exemption applicability, and emission levels. If you’re unsure whether a unit should be reported, walk through the steps below:
| Step | What to Check | What to Do |
| 1 | Is the emission unit specifically listed in your permit (ROP, Opt-Out, or PTI)? | If yes, report it. You can stop here. If not, go to Step 2. |
| 2 | Is the unit subject to permitting under Rule 201 (i.e., not exempt)? | If not Rule 201 exempt (including grandfathered units from before August 1967 that have been modified), report it. Otherwise, continue to Step 3. |
| 3 | Is the unit Rule 201 exempt? | If yes, refer to the “Rule 201 Exempt Emission Units that must be reported” Table below to determine if emissions must still be reported. If unsure, continue to Step 4. |
| 4 | Does the unit emit more than 10% of the significance thresholds in Rule 119(e)? | If yes, report it. If emissions are below 10%, go to Step 5. |
| 5 | Is the unit subject to an enforceable federal or state standard (e.g., NSPS or MACT)? | If yes, report it. |
Rule 201 Exempt Emission Units that Must be Reported
| Rule 201 Exemption | Reporting Requirement |
| Rule 281(2)(h) | Only report emissions of applicable criteria pollutants for cold cleaners having a total annual throughput greater than 1,000 gallons of cleaner (aggregate of all cold cleaners combined).
Total annual throughput of cleaner = (cleaner used) - (cleaner reclaimed as waste) |
| Rule 282(2)(b) | Only report emissions of applicable criteria pollutants from fuel burning equipment that have a total annual throughput equal or greater than any of the following: 50,000,000 cubic feet of gases in Rule 282(2)(b)(i), 400,000 gallons of fuel oil in Rule 282(2)(b)(ii), and 1,000 tons of wood in Rule 282(2)(b)(iii). |
| Rule 283(2)(c) | Report all emissions of applicable criteria pollutants if the testing medium contains a VOC. |
| Rule 283(2)(d) | Report all emissions of applicable criteria pollutants if the testing medium contains a VOC. |
| Rule 284(2)(e) | Report all emissions of applicable criteria pollutants. |
| Rule 284(2)(f) | Report all emissions of applicable criteria pollutants. |
| Rule 285(2)(g) | Only report emissions of applicable criteria pollutants for engines with 300 horsepower and larger. Exclude emergency generators whose sole function is to provide back-up power when local utility service is interrupted. |
| Rule 285(2)(l)(vi)(c) | Only report emissions of applicable pollutants for equipment operating at a rate of 30,000 cubic feet per minute or higher. |
| Rule 285(2)(p) | Only report emissions of applicable criteria pollutants for annual grain throughputs equal or greater than 4,000,000 bushels |
| Rule 285(2)(r)(iv) | Only report emissions of applicable criteria pollutants for cleaners having a total annual throughput greater than 1,000 gallons of cleaner (aggregate of all cleaners combined).
Total annual throughput of cleaner = (cleaner used) - (cleaner reclaimed as waste) |
| Rule 285(2)(aa) | Report all emissions of applicable criteria pollutants. |
| Rule 286(2)(b) | Report emissions of applicable criteria pollutants when 3,000 tons of more of plastic is processed annual (aggregate of all plastic processes combined). |
| Rule 287(2)(c) | Report all emissions of applicable criteria pollutants. |
| Rule 290 | Report all emissions of applicable criteria pollutants. |
| Rule 291 | Report all emissions of applicable criteria pollutants. |
Descriptions of Rules 280 through 291 can be accessed at Michigan.gov/Air (click on “State Air Laws and Rules” then “Part 2 Exemptions”)
If you’ve walked through all five steps and still aren’t sure whether to include a unit, you can contact your district inspector, email EGLE at [email protected], or reach out to Trinity’s Ann Arbor office for assistance in evaluating emission unit applicability and reporting requirements.
How to Complete and Submit the Form
Getting started is simple:
- Log into MiEnviro Portal and select your site
- From the Dashboard or Submissions screen, begin the Annual Equipment Inventory Review
- Update your equipment and release point data
- Validate the form, then mark it “Ready for Submission”
- Only users with certifier rights can submit the form
For step-by-step instructions on completing the Annual Equipment Inventory Review, refer to the MiEnviro Portal Annual Equipment Inventory and Annual Emissions Reporting User Guide.
After submission, EGLE staff will review your entries. If something needs to be corrected, they’ll return the form. Once approved, your inventory is locked and used to populate the upcoming Annual Emissions Report.
Planning Ahead: Why This Matters for January
Once the Equipment Inventory Review (EIR) is submitted and approved, the equipment information becomes locked and carries forward into the Annual Emissions Report (AER), which opens in MiEnviro Portal in early January and is due by March 15th.
It is critical to understand that equipment data cannot be edited during the AER process. While you will still see the same tiles such as Facility, Emission Units, Controls, and Release Points, they are view-only. The only editable section is the Process Emissions tile for each emission unit. Even small changes, such as renaming a unit or adjusting stack details, must be made during the EIR. Any changes to equipment after approval require an amendment request, which can delay reporting.
Carefully reviewing and updating your inventory during the EIR saves time, helps avoid reporting errors, and ensures a smoother AER season.
Helpful Tips for a Smooth EIR
- Start early. Don’t wait until late October to begin. The sooner you review your equipment, the more time you have to ask questions or request edits.
- Coordinate with your team. Double-check any equipment changes with operations or maintenance staff.
- Don’t guess. If you’re unsure whether an emission unit or release point needs to be included, contact your inspector or Trinity for help.
- Use the “Request an Amendment” function if changes are needed after submission.
Need Assistance?
If your site has new equipment, recently shut down a process, or simply needs a second set of eyes on the inventory, our team is here to help. Trinity’s Ann Arbor office can assist with determining what should be included and ensuring your EIR and AER submissions go smoothly. Contact us at 734.474.7709 with any questions or to schedule a review of your facility’s AEI.
