Asbestos Exposure at Stoneman Generating Station (Cassville, Wisconsin): What Former Workers and Families Need to Know
Facility: Stoneman Generating Station | Cassville, Grant County, Wisconsin Operator: DTE Stoneman LLC (formerly operated under Wisconsin Power and Light and other predecessors) Status: Retired coal-fired generating station
⚠️ URGENT Wisconsin FILING DEADLINE WARNING
**Wisconsin’s asbestos statute of limitations is 3 years under Wis. Stat. § 893.54 — and pending 2026 legislation could impose severe new procedural barriers on cases filed after August 28, 2026.
**> Every day you wait narrows your options. If you or a family member worked at Stoneman Generating Station and has been diagnosed with mesothelioma, asbestosis, or asbestos-related lung cancer, call a Wisconsin mesothelioma lawyer today — not next month, not after the holidays. Today.
The clock is running. The legislature is moving. Do not let a deadline imposed by the same industry that hid asbestos’s dangers take your compensation away.
What Former Workers and Families Need to Know Right Now
If you worked at Stoneman Generating Station during any phase of its operation — from construction through decommissioning — or if a family member did, you may have been exposed to asbestos-containing materials linked to mesothelioma, asbestosis, and lung cancer. Coal-fired power plants like Stoneman were built and operated during decades when asbestos-containing materials were standard for insulation, fireproofing, and mechanical sealing. The executives who ran these plants knew asbestos was deadly. They hid that knowledge from workers.
Workers and families seeking compensation should consult a Wisconsin asbestos attorney to understand their legal rights — including Wisconsin mesothelioma settlement options and asbestos bankruptcy trust fund claims. This article explains what reportedly happened at Stoneman, which workers faced the greatest exposure risk, what diseases result, and what legal compensation options remain available — especially for Wisconsin residents facing the Wisconsin asbestos statute of limitations.
Stoneman sits on the Wisconsin side of the upper Mississippi River — directly across from and within the same industrial corridor as major Missouri and Illinois power generation and manufacturing facilities, including AmerenUE’s Labadie Energy Center, Ameren’s Portage des Sioux Power Plant, and the heavy industrial complex surrounding Granite City, Illinois. Workers in this corridor frequently crossed state lines, worked at multiple facilities, and were represented by the same Missouri and Illinois union locals. If you or a family member worked at Stoneman and live in Missouri or Illinois, your legal rights are governed in significant part by Missouri and Illinois law — and a toxic tort attorney experienced in Wisconsin asbestos cases can guide you through your compensation options.
Wisconsin residents: You currently have 5 years from diagnosis to file under Wis. Stat. § 893.54 — but pending 2026 legislation could impose severe new barriers on cases filed after August 28, 2026. Consult a St. Louis asbestos cancer lawyer today.
Table of Contents
- What Happened at Stoneman Generating Station
- Why Coal-Fired Power Plants Used Asbestos-Containing Materials
- When Asbestos-Containing Materials Were Reportedly Present
- Which Workers Face the Highest Exposure Risk
- Specific Asbestos-Containing Products Allegedly Present
- How Asbestos Exposure Causes Disease
- Legal Rights and Compensation for Wisconsin residents
- Steps Former Workers Must Take
- Frequently Asked Questions About Stoneman Asbestos Exposure
- Contact a Wisconsin mesothelioma Lawyer
What Happened at Stoneman Generating Station
The Facility’s History and Industrial Footprint
Stoneman Generating Station sits along the Mississippi River in Cassville, Grant County, Wisconsin. It operated as a coal-fired electric generating facility for decades under several ownership structures, with DTE Stoneman LLC holding operational responsibility in its later years.
Its location on the upper Mississippi River placed it within the same industrial corridor that extends southward through Missouri and Illinois — connecting Stoneman to Portage des Sioux, Labadie, Granite City Steel, and the broader network of Mississippi River industrial facilities where the same trades, the same union locals, and many of the same asbestos-containing materials were in continuous use throughout the mid-twentieth century. Workers in this corridor commonly moved between facilities, carried work histories across state lines, and shared exposure to the same asbestos-containing products from the same manufacturers.
The plant’s industrial footprint — massive boilers, turbines, cooling systems, and miles of high-pressure steam piping — placed Stoneman squarely in the category of worksites now associated with serious occupational asbestos exposure in American industrial history.
Why Stoneman Was Built With Asbestos-Containing Materials
Coal-fired power generating stations like Stoneman were constructed during an era when asbestos-containing materials were the industry standard for high-temperature insulation, fire protection, and mechanical sealing. From the plant’s earliest operational decades through at least the 1970s and into the 1980s, asbestos-containing materials from manufacturers including Johns-Manville, Owens-Illinois, Eagle-Picher, Garlock Sealing Technologies, Armstrong World Industries, W.R. Grace, Georgia-Pacific, Celotex, Crane Co., and Combustion Engineering were reportedly integrated throughout virtually every major system in the facility.
Workers who built, maintained, repaired, and helped decommission the plant may have encountered asbestos-containing materials at nearly every stage of the facility’s operational life.
The Workers Most Affected
Generations of skilled tradespeople worked at Stoneman, including members of Heat and Frost Insulators Local 1 (St. Louis, Missouri), Plumbers and Pipefitters UA Local 562 (St. Louis, Missouri), Boilermakers Local 27 (St. Louis, Missouri), and affiliated unions representing:
- Pipefitters and steamfitters
- Boilermakers
- Insulators
- Electricians
- Millwrights
- Laborers
Many of these workers — dispatched from Missouri and Illinois union halls to job sites throughout the upper Mississippi River corridor — spent careers moving between Stoneman and facilities like Labadie, Portage des Sioux, and Granite City Steel. Asbestos litigation experts and medical researchers consistently identify long-term, repeated occupational asbestos exposure as creating the greatest risk of asbestos-related disease. Workers with multi-facility exposure histories across this corridor may have accumulated fiber burdens from multiple worksites over decades.
If you are one of these workers and you have received a diagnosis, Wisconsin asbestos law provides a path to compensation. Consult a Wisconsin asbestos attorney immediately — the Wisconsin asbestos statute of limitations is running.
Why Coal-Fired Power Plants Used Asbestos-Containing Materials
Extreme Thermal Insulation Demands
Coal-fired power plants operate at extraordinarily high temperatures and pressures. Asbestos-containing materials served several critical functions across these facilities.
Steam temperature control: Steam generated at temperatures commonly exceeding 1,000 degrees Fahrenheit required insulation capable of containing heat while protecting workers. Insulation products such as Kaylo and Thermobestos — manufactured by Owens-Illinois and Johns-Manville respectively — were reportedly specified for these applications. The same products were reportedly used at Missouri River corridor facilities including Labadie and Portage des Sioux, and members of Insulators Local 1 and UA Local 562 allegedly applied these materials throughout the region.
Boiler protection: Asbestos-containing materials were wrapped around boilers, turbines, and steam lines to prevent heat loss and protect workers from burns and scalding. Products including Aircell and Monokote spray-applied fireproofing — manufactured by Armstrong World Industries and W.R. Grace — were allegedly used extensively at facilities in this corridor.
Heat exchanger sealing: Asbestos fibers resist heat at levels no synthetic alternative matched through most of the twentieth century. Garlock Sealing Technologies reportedly supplied asbestos-containing gaskets and packing materials for heat exchanger applications throughout the region.
Pressure system integrity: High-pressure steam systems required insulation that would not degrade under sustained thermal stress. Unibestos and Cranite products from Johns-Manville and Crane Co. were among the asbestos-containing materials allegedly employed for these applications.
Fire Protection and Building Construction Standards
Power plant structures required extensive fire protection because combustible fuels were continuously processed on site. Asbestos-containing materials were reportedly applied in:
- Structural steel fireproofing using spray-applied products such as Monokote (W.R. Grace) and Aircell (Armstrong World Industries)
- Wall and ceiling panels incorporating asbestos-containing wallboard products from Georgia-Pacific and Celotex
- Spray-applied protective coatings from Johns-Manville and Eagle-Picher
- Fire-resistant flooring materials containing asbestos components
- Building envelope insulation incorporating asbestos-containing fibers
These applications were standard practice from the 1930s through the late 1970s — across every power generating facility in the Mississippi River industrial corridor, from Wisconsin south through Missouri and into Illinois.
Mechanical Sealing and Gasket Applications
Asbestos-containing sealing products were allegedly used throughout the facility in:
- Piping valve assemblies receiving asbestos-containing gaskets from Garlock Sealing Technologies and Armstrong World Industries
- Pump seal components utilizing asbestos rope packing and gaskets from Johns-Manville and Eagle-Picher
- Compressor systems sealed with asbestos-containing materials from Crane Co. and Combustion Engineering
- Mechanical equipment subject to extreme heat and pressure, employing Superex and other asbestos-containing gasket products
Asbestos-containing gaskets and packing materials from these manufacturers were the industry standard across virtually every major equipment manufacturer throughout much of the twentieth century.
Industry-Wide Standard Practice — and Industry-Wide Concealment
The use of asbestos-containing materials at facilities like Stoneman reflected universal practice throughout the Mississippi River industrial corridor. Engineering specifications mandated asbestos use. Equipment manufacturers recommended asbestos products. Federal and state regulatory frameworks permitted — and effectively required — asbestos use prior to the 1970s.
The controlling fact for litigation purposes: as the medical and scientific community developed an increasingly clear picture of asbestos’s lethal hazards beginning in the 1930s, asbestos manufacturers including Johns-Manville and W.R. Grace suppressed and minimized that knowledge. Workers at Stoneman, at Labadie, at Portage des Sioux, at Granite City Steel, and throughout this industrial region were left without adequate warning or protection — for decades.
When Asbestos-Containing Materials Were Reportedly Present
Original Construction and Early Operations
During original construction and early operational decades, asbestos-containing materials from Johns-Manville, Owens-Illinois, Armstrong World Industries, and other major manufacturers were reportedly incorporated into:
- Boiler insulation systems utilizing Kaylo and Thermobestos products
- Turbine lagging with asbestos-containing wrapping from Johns-Manville and Owens-Illinois
- Steam pipe insulation with Aircell and comparable products
- Structural fireproofing with Monokote and spray-applied coatings from W.R. Grace
- Equipment assembly with gaskets and packing from Garlock Sealing Technologies and Armstrong World Industries
Construction workers, ironworkers, and laborers who built and commissioned the facility may have encountered asbestos-containing materials throughout this process. Engineering standards of those eras specified asbestos products from Johns-Manville, Owens-Illinois, Celotex, and Georgia-Pacific as the default insulation and fire-protection materials — the same specifications used simultaneously at Labadie, Portage des Sioux, and throughout the Mississippi River industrial corridor.
Ongoing Maintenance and Repair Operations
The period of greatest exposure risk for many workers was not original construction — it was the decades of maintenance,
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