The June 16, 2026 surface-methane inspection
EGLE's Air Quality Division walked the Arbor Hills Landfill surface with methane detectors and recorded 75 areas above the 500-ppm threshold, up to 148,682 ppm at one well.
GFL took ownership of Arbor Hills Landfill on October 30, 2020, per their regulatory submission to EGLE (Nov 4, 2020, SRN N2688, signed by David Seegert).
On June 16, 2026, the Michigan Department of Environment, Great Lakes, and Energy (EGLE), Air Quality Division, conducted an announced surface emission monitoring (SEM) inspection of the Arbor Hills Landfill. Surface emission monitoring is a required walk of the landfill surface with a handheld methane detector, used to find places where gas is escaping through the cap; a reading at or above 500 ppm above background (that is, 500 ppm above the surrounding ambient methane level) counts as a recorded exceedance. This was an abbreviated, targeted survey of suspected problem areas near the active Cell 6, prompted by perimeter fenceline exceedances of the 40-ppm methane action level that the letter says have been a regular occurrence since 2022; in it, EGLE found 75 areas with surface methane above 500 ppm, the highest being 148,682 ppm at well 502R.
What this is, and is not. Under the federal NESHAP rule (40 CFR 63.1958/63.1960), these are documented exceedances that start a corrective-action clock, not, by themselves, a declared violation. EGLE's letter is explicit: if the operator records each location and completes the required cover repair or vacuum adjustment, with re-monitoring within 10 calendar days of the exceedance (that is, by about June 26, 2026), "the exceedance is not a violation." It becomes a violation only if those corrective actions are not completed. The figures and photographs below are from EGLE's own results letter and inspection photo log; they are public records, presented here without alteration.
Tracking the close-out. Each of the 75 recorded locations is a separate item the operator must correct and re-monitor. A location-by-location close-out tracker lists all 75, with what the public record shows for each.
On a map. The June 16 exceedances, alongside the routine quarterly SEM reports and the September 2025 inspection, are plotted on the surface-methane exceedance map, with the SEM5000 walk tracks for the two EGLE inspections.
The highest readings
Penetrations at elevated-temperature wells
A penetration is the point where a pipe passes through the landfill cap, a common place for gas to escape. Four of the inspection's penetration photos are labeled by the operator with wells that EGLE separately designates as elevated-temperature "Wells of Interest" or their immediate buffer.
Leachate and standing water
The inspection also noted liquid at the surface. Liquid pooling in and around the gas wells is one of the recognized signs of elevated landfill temperature, and EGLE's June 16 inspection letter reported that about half of the vertical wells showed signs of impairment — which the letter noted is above average for the landfills it inspects — with several surface-methane hits collocated with a flooded area of the well field. EGLE followed up on July 13, 2026, asking the operator for an update on the leachate observations. The operator responded on August 7 — about seven weeks after the inspection — reporting that it had investigated the four locations and attributed the darkened water to stormwater carrying finished compost, not leachate. No laboratory test of the liquid appears anywhere in the public record, and the record shows no indication that EGLE accepted the operator's explanation. Whether the liquid was leachate or stormwater is left unresolved by any measured result: either it was never tested, or any test has not been made public.
Cover and erosion
The landfill's cover (also called the cap) is the engineered layer of soil and liner placed over the buried waste, to keep rain out and hold the landfill gas in so it can be routed to the collection system. Erosion channels and tears in the cover are places where surface methane can escape.
These are 10 of the 94 photographs in the inspection's log; the reading locations were spread across the site, most concentrated near the active area and along the western ditches. A well-by-well geolocation of the full 94-photo log against EGLE's elevated-temperature roster is included in the folder below.
The documents
- The full public record of this inspection — EGLE's results letter (with the complete 75-reading table), the 94-photo inspection log, and these photographs — is in this folder: Arbor Hills Surface Emissions Inspection, June 16, 2026.
- For the fuller record, the same folder includes the operator's own August 7 response to the leachate observations, and the operator's quarterly surface-methane monitoring reports from the quarters leading up to the inspection.
Why this is on the record: the site's live elevated-temperature data — the readings that make gas escape and liquid impairment an ongoing question — is in the thermal map and the wellfield explorer. Photographs of the site's 2022 subsurface event are on the 2022 event page.