Far below Michigan waters operates a disposal system
By Mark H. Stowers
The trucks arrived in Michigan carrying liquid waste from another state’s disaster – the 2023 Norfolk Southern derailment in East Palestine, Ohio. Their destination was an industrial site in Romulus, where pumps could send the cargo more than half a mile underground. The shipments were legal, tracked by hazardous-waste manifests and bound for a permitted facility. Yet they surprised many state and local officials, exposing a contradiction that turned an obscure disposal system into a public question – when waste vanishes beneath Michigan, what keeps it there?
Any injection site, at the surface, can look almost ordinary – tanks, valves, gauges, piping and a wellhead behind a fence. The consequential machinery extends far below view. Steel casing and cement pass through shallow water-bearing layers toward porous rock selected to receive liquid under pressure. A confining formation above the disposal zone is meant to prevent upward movement, while monitoring equipment is designed to reveal a leak or pressure change.
Bill Shuster, Ph.D., a professor of civil and environmental engineering at Wayne State University, compares the process with a drinking-water well operating in reverse.
“If we want to reverse the process,” Shuster said, “instead of taking things out, we’re putting stuff in, and we’re running it really deep, like often more than four thousand feet below ground surface. A better part of a mile below ground surface.”
At that depth, he said, sandstone and other formations can contain pore spaces capable of receiving fluid.
“Liquid wastes are sent down the tube, injected into the well, and introduced to these geologic formations,” Shuster said.
Injection wells operate under the federal Safe Drinking Water Act and its Underground Injection Control program. They handle oil-field brine, industrial wastewater, hazardous liquids, solution-mining fluids and other streams, while some support production or storage. Their depths and designs vary, but the premise is the same – geology and engineered barriers must isolate injected material from drinking water for as long as it remains dangerous.
Michigan has relied on injection since the 1930s, when operators began returning oil-field brine underground instead of releasing it into streams, roadside ditches and pits. The practice reduced visible pollution but shifted the burden to geology, construction, pressure control, reporting and long-term oversight. The central question is whether each site has the right rock, sound casing, complete records, responsible operators and enough independent scrutiny to keep injected fluids from reaching drinking water.
Answering that question begins with a distinction often lost in public debate. Injection wells are not a single technology used for a single kind of waste. Their federal classifications are based on purpose, fluid and potential risk rather than depth alone.
The EPA divides injection wells into six classes covering deep industrial and municipal disposal, oil and gas operations, solution mining, generally prohibited hazardous-waste injection near drinking-water sources, varied shallow systems and long-term carbon dioxide storage. Those distinctions shape the fluid, risk and regulatory requirements.
Those categories explain what the wells do. Their history explains why Michigan uses them. Shuster described injection as a choice among imperfect disposal options.
“The benefit is that we have a way of getting rid of wastes that we don’t have a place for at the surface,” he said. “We have a way of getting rid of them that presents an acceptable level of risk, that being a low risk of further contamination.”
But the advantage comes with a condition.
“Does the maintenance and monitoring of these wells provide an acceptable risk profile?” Shuster asked. “And does it reliably carry out the service of holding wastewater that has been injected very deep into the subsurface?”
Samantha Pickering, public and environmental health policy manager for the Michigan Environmental Council, said the public-health concern begins with any pathway into groundwater.
“The main concern with them is the potential for them to leak into groundwater, which is essentially our drinking water,” Pickering said. “If that becomes contaminated in a community, that’s going to pose a variety of different public health issues, depending on what the contaminant is.”
The contents can complicate that assessment.
“Sometimes when it’s a bunch of different contaminants that they inject into the wells, that really depends on how they interact with one another, which one’s more prominent than the others,” Pickering said. “It can really be a variety of different things.”
That regulatory tradeoff grew from a period when Michigan oil and gas waste was commonly discharged into creeks, roadside ditches and pits. The 1974 Safe Drinking Water Act and Underground Injection Control rules that followed established the central requirement – underground injection may not endanger an underground source of drinking water. EPA may administer that protection directly or grant primacy to a state program that meets federal standards.
Michigan received primacy over Class II wells effective Aug. 29, 2022. EGLE’s Geologic Resources Management Division regulates those wells under Part 615 and its associated administrative rules, handling permitting, compliance monitoring and enforcement through its EPA-approved UIC program. The EPA retains oversight to ensure the state program continues to meet or exceed federal requirements.
Michigan requires Class II operators to report injection volumes, pressures, fluid chemistry and annular pressure through EGLE’s MiSTAR system; document mechanical integrity; and quickly report integrity failures. Disposal wells generally record weekly and report monthly, secondary-recovery wells report annually, and commercial wells report waste sources quarterly and need approval before accepting a new source.
Mechanical-integrity tests are required at least every five years, and a failure must be reported within 24 hours with written notice to follow. The system therefore relies on regulatory review and operator-generated data from accurate gauges, calibrated equipment, complete reports and timely disclosure.
Deep injection wells use concentric steel casing cemented to surrounding rock. Surface casing extends below usable aquifers, an inner string reaches the injection zone and tubing carries fluid downward. A packer seals the space between tubing and casing so pressure changes can be monitored.
The target is a porous formation beneath low-permeability rock such as shale or salt. Regulators assess its depth, thickness, porosity, pressure, faults and nearby wells, and require injection pressure to remain below the level that could fracture the confining zone or endanger groundwater.
“The idea is to find a layer that’s deep underground, well deeper than any freshwater zone, and then you find a layer between that zone and the near-surface freshwater that would block fluid flow,” said William B. Harrison III, Ph.D., professor emeritus and research director for the Michigan Geological Repository for Research and Education and the Michigan Geological Survey. “And then you seal it in there.”
The second line of defense is the well itself. Deep wells may pass through freshwater aquifers on the way to an injection zone, so steel casing and cement must isolate the wellbore from surrounding rock and water-bearing layers.
“You would pass through it, but the idea is you build the well so that the pipe is totally sealed,” Harrison said, “and then you pump cement down along the sides of the pipe, so it’s isolated from any of the surrounding rocks or sand and gravel layers.”
Those barriers address the primary hazard shared by every class – unintended movement of injected fluid into drinking water. Other hazards vary by fluid, pressure, depth, chemistry and the age and construction of nearby wells.
Class I wells inject industrial or municipal waste beneath the lowest underground source of drinking water. Some receive hazardous waste, making failed casing, poor cement bonding, incompatible chemistry, excessive pressure, faults or old wells especially consequential.
“The Class I wells, those are the most hazardous and toxic, and they have the strongest regulations and the strongest monitoring,” Harrison said.
Safety depends on exhaustive site characterization, compatible waste chemistry, redundant casing and cement, pressure limits, continuous or periodic monitoring and proof that the well retains mechanical integrity. Permitting can take years.
“It’s a very detailed process,” Harrison said, “and there’s probably several dozen experts that have studied these rocks and know what the regulations are that have to review those permit applications.”
The work does not end when injection begins. “Most of these disposal wells have surveys that they have to do,” he said. “They have to go in and test the well to make sure that it doesn’t have any leaking in it.”
Class II wells inject fluids associated with oil and natural-gas production for brine disposal, enhanced recovery or certain hydrocarbon-storage purposes. In Michigan, the long legacy of oil and gas drilling makes older wells potential migration pathways if injection pressure moves fluid beyond the intended formation.
Produced brine can be extremely salty and damaging at the surface. “You don’t want really super salty water laying around on the earth’s surface,” Harrison said. Returning it underground removes one hazard but creates another set of obligations – control pressure, verify casing and cement, account for nearby wells and monitor for leakage.
Injection also has been associated in some regions with induced earthquakes when pressure reaches a favorably oriented fault. That hazard is site-specific, and managing it requires attention to injection rate, pressure, local geology and seismic response.
Michigan also uses wells for underground gas storage, a function Harrison compared with “a big savings account” that can be drawn down during severe winter weather. Storage introduces different risks, including gas migration, loss of containment and surface equipment failures. The safeguards remain familiar – sound geology, tested wells, pressure control and long-term surveillance.
Class III wells are used to extract minerals by injecting fluid underground. In Michigan, the best-known example is solution mining of salt. Water is pumped into a salt-bearing formation, dissolves the mineral and returns to the surface as brine.
“One of the common ways of mining salt is by solution mining,” Harrison said. “You pump a bunch of water down and dissolve the salt layers. Then you pump that brine back up to the surface and dry it out, and you get salt.”
The principal hazards differ from waste disposal. Operators must control the shape and stability of the underground cavity, prevent unintended vertical or lateral migration of brine and protect aquifers while cycling large volumes through the well. Poorly controlled dissolution can weaken rock, contribute to subsidence or create an unstable cavern. Mechanical integrity testing, cavern modeling, pressure limits and careful closure planning reduce those risks.
Class IV wells inject hazardous or radioactive waste into or above formations that contain an underground source of drinking water. That proximity makes the basic design incompatible with modern groundwater protection. New Class IV disposal wells are generally prohibited. Limited uses may be authorized as part of federal or state groundwater remediation projects, where injection is intended to treat contamination rather than dispose of waste.
The danger is direct – contaminants have little or no geologic separation from usable water. Safety therefore comes chiefly from prohibition, strict identification and closure of improper wells, and tightly controlled remediation exceptions.
Class V is the catchall. It includes a wide variety of wells that do not fit Classes I through IV or VI, often injecting nonhazardous fluids into or above underground drinking-water sources. Depending on design and use, that may include stormwater drainage, aquifer recharge, heating and cooling return flow or other commercial and industrial systems.
Because many Class V wells are shallow, the hazard is less about extreme depth and pressure and more about what enters the well at the surface. A poorly managed drain can become a direct route for fuel, solvents, pesticides or contaminated runoff. Protection depends on inventory, source control, proper siting, maintenance and closure when a well cannot operate without endangering groundwater.
Harrison offered a reminder that not every injection project involves highly toxic material. A temporary well might handle muddy water from a quarry, for example. “Sometimes it’s a very short-term thing,” he said. “And once that project’s done, that well’s no longer a benefit to anybody, and so they’ll just fill it in.”
Class VI wells store carbon dioxide in deep formations, where buoyancy, faults, old wells and chemical reactions can threaten containment. Safeguards include mapping and modeling the storage formation, confining zone, plume and pressure front; monitoring movement; testing well integrity; and maintaining closure and post-injection plans to protect drinking water and prevent atmospheric release.
For hazardous waste, the underground well may not be the only or even the greatest exposure point. Waste must be loaded, transported, unloaded and handled before injection.
“That’s probably worse than once you get it underground,” Harrison said. “There’s not a whole lot underground that’s going to mess with it.”
Transportation crashes, transfer spills, equipment failures and worker exposure are part of the full risk picture. So is chemical compatibility. “You have to analyze not only what the geology is or the layers that you’re sticking this stuff in,” Harrison said, “but you also have to think about what the chemistry of the fluid is that you’re putting down there.”
Steel corrodes. Cement can crack. Pressure changes. Records can be incomplete. A safe well is not simply one that was properly designed years ago. It is one that continues to be tested, maintained and managed.
Harrison said small defects can sometimes be found before they become large failures.
“Sometimes it’s just a little pinhole, and if they identify that, they can go in and seal that up,” he said. “If you catch it before it goes too much, then you don’t have a very big problem. If you wait and don’t treat it, then you have a real big problem.”
Closure also matters. Wells that are no longer used must be plugged in a way that prevents them from becoming conduits between formations.
“There’s a regulatory process for closing a well too,” Harrison said. Operators must demonstrate proper filling and restore the surface.
Michigan’s injection landscape includes active wells, inactive wells and wells drilled for purposes ranging from waste disposal to energy storage. Public understanding begins with knowing which kind is nearby, whether it is active, what it injects and who regulates it.
The final safeguard, then, is sustained attention – by operators, regulators and communities.
“As humans, we’ve been able to figure out to do a lot of really cool and interesting things to make our lives better,” Harrison said. “But at the same time, we can’t just do it and then forget it.”
Michigan well counts vary because inventories include different classes, purposes and statuses. The EPA’s annual inventory includes proposed, under-construction, active and temporarily abandoned wells, while oil-and-gas databases may also display production, storage, enhanced-recovery, plugged and orphaned wells. A point labeled injection may therefore represent gas storage rather than commercial waste disposal.
EPA’s inventory, posted February 5, 2026, is the latest national inventory. Because it combines proposed, under-construction, active and temporarily abandoned wells, its Michigan totals should not be mistaken for a count of active waste-disposal wells.
EPA’s inventory, reviewed Oct. 4, 2026, identifies 25 Michigan wells – four hazardous and 21 nonhazardous. The hazardous group includes two commercial Republic wells in Romulus and two noncommercial Pharmacia and Upjohn wells in Kalamazoo County. Oakland, Macomb and Monroe counties have no Class I wells; Wayne County has eight, including five Buckeye brine-disposal wells, one Sun Pipeline well and Republic’s two hazardous-waste wells. These figures exclude Class II and other UIC classes.
Eric Kimber, a certified professional geologist and manager of EGLE’s Underground Injection, Storage, and Carbon Management Section, said GRMD regulates about 1,120 active UIC wells under Parts 615 and 625 – approximately 23 Class I, 1,050 Class II, 32 Class III and 15 Class V wells used for spent or processed brine disposal. The total changes as wells are plugged, drilled or converted and excludes injection-withdrawal wells for natural-gas or liquefied-petroleum-gas storage and most Class V wells outside GRMD’s authority.
Of Michigan’s approximately 1,050 active Class II wells, about 622 are disposal wells and 428 are enhanced-recovery wells. Disposal wells accept fluids directly associated with oil or natural-gas production, primarily brine separated at production facilities and injected into deep, confined formations. Michigan currently has no active Class II liquid-hydrocarbon storage wells.
The Michigan Geological Repository for Research and Education, part of the Michigan Geological Survey, contains 5,894 well records, including 23 Oakland County entries. The county’s small inventory is dominated by natural-gas storage but also includes oil-field and industrial activity. The repository cautions that large historical inventories can contain errors and should be assessed for fitness of use.
A well can be easy to overlook from the surface. In the survey, Oakland County appears only 23 times among 5,894 records – less than half of one percent. Yet those entries tell a more varied story than the phrase injection well suggests. Some wells are associated with storing natural gas for later use. Others are classified for brine disposal, gas injection or mineral-waste disposal.
Natural-gas storage dominates Oakland’s entries. Fourteen of its 23 records carry the GS designation, and 12 are marked active. The active records name Consumers Energy as operator and are found in Lyon and Northville. A gas-storage well is not simply a place to discard material. Michigan defines it as a well used to move natural gas into and out of a designated underground reservoir. The lists those Oakland-area fields among Consumers Energy’s storage operations.
These Oakland County natural-gas storage records are outside Kimber’s approximately 1,120 active-well total because injection-withdrawal wells used for underground natural-gas storage are not UIC-classified wells.
Beyond the storage fields, Oakland’s records point to different industries – and different reasons for putting a well underground. A CMS Gas Transmission entry in Addison is classified BDW, a brine-disposal well type used for brine produced with oil and gas. Entries naming Hawkins Oil of Michigan and Energex Petroleum are classified GIW, gas-injection wells. Michigan says that type can be used for disposal or to maintain pressure and aid recovery in a producing reservoir.
A J and J Investments in White Lake is classified MDW, the state’s mineral-well category for subsurface disposal of waste products or processed brine. A Royal Oak entry names Reichhold Chemicals, but its OTI code is not defined on the state well-type reference page so its specific use should not be inferred from the company’s name.
Oakland County’s records sit within a statewide inventory that spans natural-gas and liquefied-petroleum-gas storage, brine disposal, water injection and solution mining. The mix connects Michigan’s well network to gas utilities, oil-and-gas operators, and mineral and chemical industries rather than to a single injection-well industry.
Oakland’s 23 spreadsheet entries include 12 active, eight plugging-approved and three shut-in records, but they do not represent 23 separate wells. Two API identifiers each appear three times, leaving 19 distinct identifiers.
The safest reading is therefore both specific and modest. Oakland’s listed activity is led by active natural-gas storage, while its other entries document a smaller, mixed legacy of gas injection, brine and mineral-waste disposal, and wells no longer recorded as active.
Oakland County Water Resources Commissioner Jim Nash said the issue matters to residents even though injection-well regulation falls outside his office.
“First of all, I have to say that my office really has no jurisdiction or responsibility regarding mineral extraction and specifically injection wells,” Nash said. “There is always concern for the aquifer and folks should test their well water regularly. Local governments have no control or responsibility for regulating mineral extraction, especially oil and gas.”
The jurisdictional gap helps explain local frustration. County officials may hear concerns about aquifers, emergency response and private wells, but state and federal agencies make the permitting decisions. The nearest high-profile commercial hazardous-waste injection operation for metropolitan Detroit is in Wayne County, not Oakland County.
“It’s important that all this stuff is made public,” Harrison said. “And it’s out there. I mean, if you know where to look, you can find all this kind of data.”
Depth provides separation, not immunity. Deep Class I and many Class II wells pass through comparatively shallow freshwater aquifers before reaching injection formations thousands of feet lower, making protection dependent on casing, cement, confining rock and controlled pressure rather than distance alone.
Kimber said wells regulated by the Geologic Resources Management Division are built with at least two primary strings of steel casing.
“The larger surface casing generally extends at least 100 feet below the base of glacial drift into competent bedrock or at least 100 feet below all underground sources of drinking water, whichever is deeper, and is cemented back to the surface,” Kimber said.
A smaller injection string, also called the long string, is installed inside the surface casing and extends to the approved injection zone.
“Together, the multiple casing strings and cementing provide barriers against the movement of subsurface fluids into USDWs,” Kimber said, using the regulatory shorthand for underground sources of drinking water.
“For most GRMD-regulated injection wells, a tubing string is installed inside the long string along with a packer, creating another layer of isolation and a dedicated pathway for injected fluids,” Kimber said. “The packer seals the annular space above the injection interval and allows the tubing-casing annulus to be monitored for a loss of mechanical integrity.”
Shuster described casing as the engineered barrier that keeps waste from traveling where it does not belong.
“The point is that you’re setting this well and creating a confining casing all the way down,” he said. “If wastewater creeps along the outside or the casing cracks, then that’s a problem.”
Before injection begins, regulators may require logs, pressure tests and a mechanical-integrity demonstration. A well must show that there is no significant leak in the casing, tubing or packer and no significant movement of fluid through channels outside the casing. During operation, unexpected changes in annular pressure, injection pressure or volume can signal trouble. Temperature, radioactive-tracer, cement-bond and other logs can help identify pathways.
The “area of review” around a proposed well is equally important. Old production wells, dry holes and abandoned borings can become vertical conduits if they intersect the pressure-influenced zone. A technically sound new well can still pose a problem if nearby legacy wells were poorly plugged or their records are incomplete. Critics, including Michigan Citizens for Water Conservation, argue that older wells near injection sites deserve more scrutiny for precisely this reason.
When a well reaches the end of its life, plugging is intended to restore isolation between formations. Cement plugs are placed at specified depths and equipment is removed or cut off. Long-term stewardship matters because buried waste remains after a company changes ownership or a facility closes. Financial-assurance requirements are supposed to ensure money is available for plugging, but the history of orphaned oil and gas wells nationally shows how liabilities can outlast operators.
EGLE-GRMD regulates Class II wells under Part 615 and its EPA-approved UIC program. It regulates Class I, Class III and select Class V wells under Part 625, while EPA directly administers federal UIC requirements for those classes because Michigan lacks primacy. Those operators must satisfy both state and federal rules governing construction, testing, operation, reporting and plugging, with additional hazardous-waste requirements where applicable.
Kimber provided a concrete figure for the state’s field network.
“Field inspections of the UIC wells and associated facilities are conducted primarily by GRMD’s 25 area geologists, who are assigned to one of six District offices located throughout the state,” he said. “Those area geologists conduct routine lease inspections to evaluate wells and facilities for regulatory and permit compliance, including potential maintenance or operational issues.”
Oversight continues after a site visit.
“GRMD also reviews operator-submitted monitoring and operating data, injection pressures and volumes, mechanical integrity test results, electric logs, bottom-hole pressure tests, fall-off tests and other required reports,” Kimber said. “Staff evaluate the information for changes in injection performance or potential concerns that might require communication with the operator, additional technical evaluation or follow-up inspections.”
Public transparency is part of that oversight. MiSTAR contains Class II reporting; EGLE’s GeoWebFace map provides well records and geologic information. EPA posts permits, inventories and regional notices; and hazardous-waste manifests track shipments. But those systems serve different purposes and do not always align neatly. A resident trying to learn what is beneath a particular township may have to move among several databases, understand technical well statuses and distinguish a water well from an oil well, an injection well from a storage well and an active permit from an abandoned location.
The oversight network stretches across a well field shaped by both geology and industry. Oil-and-gas injection is concentrated in parts of the Lower Peninsula where petroleum production and storage developed. Northern and rural counties contain dense clusters because that is where many producing fields and gas-storage formations lie. Commercial and industrial Class I wells follow a different map, appearing near factories, chemical plants, food processors and transportation infrastructure.
That geography can create the impression that injection is pushed into places with fewer people and less political power. Rural communities may indeed face a disproportionate share of oil-field infrastructure, along with fewer local reporters, technical consultants and emergency resources. Yet injection is not exclusively rural. EPA’s Class I list includes wells in Wayne County, and maps show oil, gas or injection-related sites in southeastern Michigan. The Romulus hazardous-waste wells place the issue squarely inside metropolitan Detroit’s industrial corridor.
Michigan’s hazardous-waste burden is concentrated in metropolitan Detroit. A 2023 Planet Detroit analysis of federal data found that Michigan facilities managed 695,000 tons of hazardous waste in 2019 – more than facilities in 42 states – and that the region contained 10 of Michigan’s 15 hazardous-waste facilities. The commercial Romulus wells, major hazardous-waste processors and landfills, transportation corridors and local emergency-response obligations make the issue broader than injection alone.
The East Palestine shipments showed that Michigan facilities accept out-of-state waste. EGLE said the Romulus operation and Van Buren Township’s hazardous-waste landfill routinely handled waste from Michigan and elsewhere under required manifests, although officials did not have to be notified of each load. More than 300,000 gallons of derailment wastewater were injected in Romulus, while roughly 360 to 400 tons of contaminated soil went to the landfill.
Wayne Disposal is one of the nation’s largest hazardous-waste landfills by volume. Both it and the Romulus injection operation are owned by Republic Services. The common ownership links two different disposal systems in western Wayne County – liquids injected into deep rock and contaminated solids buried in a hazardous-waste landfill.
That gap between legal tracking and public notice created anger. Five trucks carrying liquid reported to be mostly water with a small percentage of vinyl chloride-related contamination arrived after the derailment. The waste stream was paused after officials objected. The controversy was not simply about whether the facility was permitted. It was about who gets to decide that another state’s disaster will be managed beneath a Michigan community and when residents have a right to know.
The Romulus operation is sensitive because it is both commercial and hazardous. EPA’s Region 5 listing identifies hazardous Class I wells at the site. Commercial status means the facility can accept waste from outside companies rather than serving only an adjacent plant. Hazardous status subjects the wells to stringent construction, monitoring and waste-characterization requirements, including federal restrictions on land disposal.
EPA renewed the Romulus facility’s federal land-disposal restriction exemption effective December 23, 2025. In its decision, the agency said the operator had demonstrated to a reasonable degree of certainty that hazardous constituents would not migrate out of the injection zone or into an underground source of drinking water for at least 10,000 years. The approval covers the two Class I hazardous wells and only the waste codes identified by EPA. That modeled assurance is central to the regulatory case for continued operation, while critics focus on the assumptions, well integrity and monitoring needed to make a 10,000-year prediction meaningful.
The facility’s compliance history complicated official reassurances. EGLE’s July 2022 inspection cited waste identification, manifesting, labeling, an unapproved containment modification, inspection procedures and tank-system requirements. A January 2023 inspection found labeling and alarm-system issues. EGLE reported no environmental release, and follow-up work resolved the violations.
Those findings did not prove that the injection wells leaked. They did show why residents distinguish between a permit on paper and compliance in practice. A deep-well system includes far more than the borehole. Waste must be correctly identified, unloaded, sampled, stored, routed and injected. Failures at the surface can expose workers or neighbors even if the underground formation performs exactly as designed.
Republic Services did not respond to interview requests for this story. The company has publicly described safety and environmental compliance as priorities. Industry argues that interstate disposal is a practical feature of a specialized market because not every state or generator has access to a facility permitted for a particular waste stream. Centralized disposal can move waste to experienced operators and engineered controls, although it also concentrates risk in host communities.
The opposing view is that Michigan has become part of a national waste trade without a transparent public conversation about cumulative burden. Landfills already accept out-of-state material. Hazardous-waste injection adds a second pathway, one less visible because the final destination is deep rock. The East Palestine episode showed that a shipment can be legal and manifested while still arriving as a surprise to the host community.
Romulus also reveals the limit of a permit as reassurance. Regulators do not claim that injection wells can never fail. Their position is narrower – wells that are properly sited, constructed, operated, monitored and closed can protect underground sources of drinking water. That conditional language carries the weight of the system because every safeguard depends on continued performance, not simply approval on paper.
The principal failure pathways include corrosion or cracking in casing and cement, leaks in tubing or packers, excessive pressure, migration through faults or old wells, surface spills and, in some regions, induced earthquakes.
Distance from drinking water reduces risk but does not erase it. Waste does not need to travel straight upward through thousands of feet of intact rock to create a problem. It can move laterally within a formation until it encounters a fault or an inadequately plugged well. The practical question is whether regulators and operators have identified those pathways and can detect movement before a drinking-water source is affected.
Shuster said subsurface formations are connected to one extent or another, but movement at a properly selected site is expected to be extremely slow.
“It’s just the amount of time it would take, if ever, for the injected wastewater to migrate to a lake or somehow work its way upwards through confining geological formations,” he said. “This would be over the course of millennia.”
That confidence is conditional.
“We’re relying on the weight of evidence here,” Shuster said. “It’s unlikely that this wastewater will find its way into contact with us or with terrestrial and aquatic ecosystems.”
A fissure, an old borehole or another unexpected pathway could accelerate movement, which is why permit geology and monitoring data matter.
Kimber said EGLE’s modern UIC record has not identified drinking-water impacts linked to subsurface injection under GRMD authority.
“Since the establishment of the modern UIC regulatory framework under the federal Safe Drinking Water Act, GRMD has not identified evidence indicating that subsurface injection from UIC wells regulated under our authority has impacted underground sources of drinking water,” he said.
Kimber drew a distinction between underground migration and aboveground incidents.
“Surface spills or releases have occurred at or near injection facilities due to issues involving flowlines, surface equipment, transportation activities, or wellhead components,” he said. “When those incidents occur, operators must promptly contain the release and carry out remedial actions to meet applicable Part 201 cleanup criteria and Part 615 or Part 625 requirements.”
National experience shows that failures vary by geology and well type. Investigations have documented oil-field waste reaching the surface, treated sewage migrating toward aquifers, induced earthquakes linked to disposal in Texas, Oklahoma and Ohio, and California wells injecting into formations connected to protected water. These cases do not prove that Michigan wells are failing, but they underscore the need for complete records, adaptive oversight and site-specific monitoring.
The risk also changes with what goes down the well. Oil and gas operations bring naturally occurring brine to the surface along with hydrocarbons. That produced water can contain high concentrations of salts, hydrocarbons, metals and naturally occurring radioactive materials. Hydraulic fracturing adds water and chemicals before a well produces. Some fluid returns as flowback, and more formation water can emerge over the well’s life. Class II disposal wells receive these oil- and gas-related liquids.
Not every Michigan Class II well is a fracking-waste well, and not every fluid is imported. Many are part of longstanding local fields. Commercial disposal wells can accept fluids from multiple sources, however, and source reporting is essential to understanding whether waste crossed county or state lines. EGLE requires commercial operators to identify sources quarterly and seek approval before a new fluid source is injected.
Landfill leachate occupies a different regulatory lane. Rainwater percolating through buried waste can dissolve organic chemicals, metals, ammonia and salts. Some landfills collect and treat leachate through wastewater systems. Others use permitted deep injection or recirculation. A Waste Management fact sheet for the Autumn Hills facility describes a deep injection system designed to place treated or managed liquid in a confined formation. The exact classification, pretreatment and permit conditions matter more than the general word “leachate.”
What happens underground cannot be separated from the journey above it. Produced water may move from an oil or gas site by flowline, pipeline, vacuum truck or tanker. Industrial liquids commonly arrive by permitted tanker, although rail can serve a facility with the right infrastructure. At the well site, fluids may be transferred into tanks for short-term storage or treatment before pumps send them down the well under controlled pressure.
“Depending on the proximity of the fluid source, delivery to the facility may be by flowline or pipeline, truck, or by rail,” Kimber said, noting that rail applies to one Michigan location. “From the surface facility, fluids are moved through piping to the injection well and pumped down the wellbore under controlled operating conditions into the approved subsurface injection zone.”
Pickering said tanker movement is the most familiar part of the chain. She connected her work on injection wells to both oil-and-gas residuals and landfill leachate – the contaminated liquid collected as water passes through buried trash.
“All the stuff that ends up essentially just deteriorating from landfills ends up as leachate,” she said.
Every transfer creates risks separate from the well itself. Trucks can crash, hoses and tanks can leak, equipment can fail and labels can be wrong. A complete account of underground disposal therefore begins above ground with the generator, waste code, transporter, route, transfer equipment and emergency plan.
Senate Bills 246 and 247, introduced by Sen. Darrin Camilleri (D-Trenton), on April 23, 2025, passed the Senate on August 26 and remained in the House Natural Resources and Tourism Committee as of October 2026. The measures would tighten hazardous- and solid-waste policy, address radioactive material, create a statewide management plan and impose an inflation-adjusted fee of .417 cents per gallon on waste injected into Michigan’s two Class I multi-source commercial hazardous-waste wells, both in Romulus, with revenue directed to a host-community fund.
After Senate passage, Camilleri said, “The constituents and communities I represent have been demanding action to keep them safer, and I’m proud to deliver on that effort today.” He added, “While private waste companies profit, our residents and local governments have had no say in the types of dangerous waste being buried in their backyards. By better regulating this industry, the entire state will benefit.”
Camilleri had pressed the issue after East Palestine waste arrived in 2023, securing $500,000 for EGLE oversight and monitoring.
“We need to be watching privately-owned facilities like this closely to make sure they’re keeping our land, our water, and our communities safe, and also to make sure that events like last week don’t ever happen again,” he said at the time.
Rep. Reggie Miller (D-Van Buren Township) said the debate reaches beyond technical permit language.
“From a policy standpoint, the issue ultimately comes down to public trust,” Miller said. “Residents want to know that facilities handling hazardous materials are being closely monitored, that regulators are enforcing the law, and that local communities have a meaningful voice in decisions that may affect their health, drinking water resources, environment, and quality of life.”
“I believe transparency, strong oversight, meaningful public engagement, and accountability should remain at the center of the discussion,” Miller said.
Pickering placed the issue within Michigan’s broader waste economics.
“Michigan is dirt cheap,” she said of the state’s disposal costs. “That’s why we end up getting a lot of waste from the surrounding Great Lake states as well as Canada because it’s just cheaper for them to bring it here.”
The remark describes a policy incentive rather than proving the origin of any particular injected load, but it captures the concern behind the proposed fees and host-community support.
The bills address part of the conflict, but not its deepest uncertainty. Underground waste can outlast operators, elected officials and public attention. A permit may remain active through several administrations. An injected plume may continue moving after the last truck leaves and after the company that accepted the waste changes hands. Communities are being asked to trust not only today’s rules and inspectors but also tomorrow’s budgets, databases, owners and enforcement decisions.
Michigan’s underground-disposal system replaces a visible pollution problem with a long-term test of institutional reliability. Its engineering promise is straightforward – confine injected material, control pressure and protect drinking water. Keeping that promise depends on sound casing, accurate records, vigilant inspectors, responsible operators and public access to evidence long after the final load is injected.
