About Thomas Hill Energy Center Clifton

The Thomas Hill Energy Center, operated by Associated Electric Cooperative in Clifton Hill, Missouri, has employed area residents for decades. Like many industrial facilities and power plants along the Mississippi River industrial corridor, including Labadie Energy Center or Portage des Sioux Power Plant in Missouri, or Granite City Steel in Illinois, constructed before the 1980s, the Thomas Hill Energy Center reportedly contained asbestos-containing materials (ACMs).

Asbestos was once a “miracle mineral.” Its resistance to heat, electricity, and chemical degradation, plus its durability, made it a widely adopted material for power generation facilities like the Thomas Hill Energy Center through much of the 20th century. This widespread use means that asbestos exposure Missouri workers faced was often significant. Asbestos was allegedly present in many building materials and industrial products at power plants. These included:

  • Boiler insulation: Used to withstand high temperatures and improve efficiency.
  • Pipe insulation: Maintained steam and water temperatures within piping systems.
  • Gaskets and packing: Used in pumps, valves, and other equipment to prevent leaks. gaskets and packing’ products, including gasket material gaskets, may have been present.
  • Refractory materials: Lined furnaces and other high-temperature areas. ’s spray fireproofing** and ceiling tile’s pipe and block insulation were reportedly used as spray-on fireproofing and insulating materials.
  • Electrical components: Found in wiring insulation, panel boards, and various electrical apparatus.
  • Floor tiles and mastics: Valued for durability and fire resistance. and ceiling tile manufactured asbestos-containing floor tiles.
  • asbestos-cement board panels: Used as a durable, fire-resistant construction material for walls and ceilings. ’s asbestos-cement board** products were widely adopted.
  • Brakes and clutches: Incorporated into heavy machinery and vehicles used on-site.

The facility operated from 1966 through 1982 with 3 documented units. Equipment manufacturers included General Electric and Westinghouse (turbine and generator), Research-Cottrell and Peabody Engineering (particulate control), and Burns & McDonnell (architect/engineer), with construction by multiple contractors.

General Equipment at Thomas Hill Energy Center Clifton

The equipment below represents the systems and infrastructure documented or typically present at this facility during the era when asbestos-containing materials were specified in industrial construction. This is general facility-equipment reference — not a legal attribution of any specific product, manufacturer, or exposure event to this facility. Material-category and manufacturer information is addressed in the AsbestosIndex Product Crosswalk linked under the records table below.

Boilers View crosswalk › Steam Turbines View crosswalk › Steam Traps View crosswalk › Condensers View crosswalk › Feedwater Heaters View crosswalk › Cooling Towers View crosswalk › Pipe Insulation View crosswalk › Block Insulation View crosswalk › Refractory Lining View crosswalk › Valves View crosswalk › Gaskets View crosswalk › Pumps View crosswalk ›

Documented Asbestos Evidence

The records below are verified, state-documented asbestos removals at this facility. Each entry represents a regulated abatement project where the Missouri Department of Natural Resources (Missouri DNR) was notified under federal NESHAP rules, the work was logged, and the asbestos-containing material was confirmed and removed under regulated conditions. These are not allegations or estimates — they are paper records tying documented asbestos-containing material to this specific site.

Official Missouri Department of Natural Resources (MDNR) NESHAP (National Emission Standards for Hazardous Air Pollutants) records document asbestos abatement projects at the Thomas Hill Energy Center. These records document 50 separate asbestos abatement projects at the facility, from 1996 through projected work in 2026. These MDNR records show removal of various ACMs:

  • Boiler insulation: Noted as “friable boiler insulation” in many records (e.g., ID:A7524-2017, ID:A8021-2019, ID:A8508-2022) (documented in NESHAP abatement records). This may have included products like pipe covering or calcium silicate insulation.
  • Pipe insulation: Consistently listed as a significant material removed, often in large linear foot quantities (e.g., 400 ln. ft. in ID:193-95, 1,500 ln. ft. in ID:A4849-2008, 1,199 sf in ID:A6084-2013) (documented in NESHAP abatement records). This could have involved pipe insulation or other forms of thermal system insulation from manufacturers like.
  • Equipment insulation: Referenced in early records (e.g., ID:193-95) (documented in NESHAP abatement records).
  • Floor tile and mastic: Documented for removal (e.g., 500 sf frbl floor tile/mastic in ID:A6612-2015) (documented in NESHAP abatement records).
  • Surfacing material: Noted in several early 2000s records (e.g., ID:3091-2002) (documented in NESHAP abatement records). This may have included products like spray fireproofing or pipe and block insulation.
  • Tank insulation: Identified as “friable tank insulation” (e.g., ID:A7524-2017) (documented in NESHAP abatement records).
  • Asbestos block insulation: Specifically mentioned in older records (e.g., 50 sq. ft. in ID:1089-97, 18 sq. ft. in ID:1311-97) (documented in NESHAP abatement records). Products like block insulation from were forms of asbestos block insulation.
  • Thermal System Insulation (TSI): A broad category often encompassing boiler and pipe insulation (e.g., 300sf frbl TSI in ID:A6706-2015, 600sf frbl TSI on DA heater in ID:A6782-2015) (documented in NESHAP abatement records). The extensive and long-term nature of these abatement projects suggests workers at the Thomas Hill Energy Center may have been exposed to asbestos-containing materials from manufacturers like, and ceiling tile during the facility’s operational history, particularly before and during these removal efforts.

Material Categories in Documented Records

The materials documented above (and similar asbestos-containing materials commonly encountered in records of this type) appear in the AsbestosIndex catalog with historical manufacturer and trust-fund information. Click a category to view manufacturers historically associated with that material:

Thermal System Insulation View crosswalk › Asbestos-Cement Board View crosswalk › Pipe Insulation View crosswalk › Roofing & Flashing View crosswalk › Spray Fireproofing View crosswalk › Floor Tile & Mastic View crosswalk › Ceiling Tile View crosswalk › Gaskets & Packing View crosswalk ›

Who May Have Been Exposed at Thomas Hill Energy Center Clifton

Given asbestos use in power plants, many trades and personnel at the Thomas Hill Energy Center may have faced potential exposure. These include:

  • Insulators: Often directly handled and installed asbestos-containing insulation like pipe covering, calcium silicate insulation, and pipe insulation on boilers, pipes, and other equipment. They frequently removed it. Members of Heat and Frost Insulators Local 1 (St. Louis, MO) or Heat and Frost Insulators Local 27 (Kansas City, MO), if working at this facility, may have been exposed.
  • Pipefitters: Cut, fitted, and repaired pipes often insulated with asbestos-containing materials. This potentially disturbed fibers from products like pipe insulation. Members of Plumbers and Pipefitters UA Local 562 (St. Louis, MO) or Plumbers and Pipefitters UA Local 268 (Kansas City, MO), if working at this facility, may have been exposed.
  • Boilermakers: Worked extensively on and around boilers, heavily insulated with ACMs such as pipe covering and calcium silicate insulation, during construction, maintenance, and repair. Members of Boilermakers Local 27 (St. Louis, MO), if working at this facility, may have been exposed.
  • Electricians: May have encountered asbestos-containing materials in electrical conduits, wiring insulation, and panel boards, potentially including products from .
  • Maintenance Workers: Performed routine repairs and upkeep, often disturbing existing ACMs from various manufacturers.
  • Laborers: Assisted various trades and may have been present in areas where asbestos fibers were released from products like spray fireproofing or pipe and block insulation.
  • Welders: Their work could have disturbed asbestos-containing materials in nearby structures or insulation.
  • HVAC Technicians: Worked with ductwork and ventilation systems that may have contained asbestos components or were insulated with ACMs.
  • Custodial Staff: Could have been exposed to asbestos fibers settled as dust, potentially from deteriorating floor tiles or joint compound wallboard reportedly containing asbestos.
  • Construction Workers: Involved in original construction or later renovations, which may have involved installing or disturbing ACMs, including ’s asbestos-cement board** panels, ’s products, or materials from ceiling tile. Family members of these workers in Missouri and Illinois may also be at risk through “take-home” exposure, where asbestos fibers were unknowingly carried home on clothing, skin, or hair.

Critical Filing Deadline & Next Steps

Missouri law gives mesothelioma and asbestos-disease claimants 5 years from the date of medical diagnosis to file a personal-injury lawsuit (Mo. Rev. Stat. § 516.120). For wrongful-death claims after an asbestos-related death, the filing window is 3 years from the date of death (Mo. Rev. Stat. § 537.100). The two deadlines run on separate tracks — preserving one does not extend the other.

The personal-injury clock runs from diagnosis, not from exposure. Mesothelioma latency is typically 20 to 50 years, so workers exposed in the 1950s–1980s are being diagnosed today.

Practical first steps

  1. Document what you remember. Pay stubs, W-2s, union cards, photographs, coworker names, and dates of employment. The WorkChain widget on this page can save a copy you can email yourself.
  2. Preserve medical records. Pathology reports, biopsy results, imaging, and pulmonary-function tests are central to both civil claims and trust-fund filings.
  3. Identify household members. Spouses who laundered work clothing and children of plant workers are eligible for secondary-exposure claims when diagnosed with an asbestos-related disease.
  4. Speak with an asbestos attorney with Missouri experience. The first conversation is free and confidential. Asbestos trust-fund claims and civil claims run on different tracks — both can be pursued in parallel.

Asbestos-Related Diseases

Asbestos fiber exposure can cause several specific diseases that typically appear decades after the original exposure. The latency period — the gap between exposure and diagnosis — usually runs 20 to 50 years. That's why workers exposed in the 1960s, 1970s, and 1980s are receiving diagnoses today.

Mesothelioma

A rare, aggressive cancer that affects the lining of the lungs (pleural mesothelioma), abdomen (peritoneal), or heart (pericardial). Mesothelioma is almost exclusively caused by asbestos exposure, which is why a mesothelioma diagnosis often points directly to historical workplace exposure. Average latency from first exposure to diagnosis is 30-50 years.

Asbestosis

A chronic, non-cancerous scarring of lung tissue caused by inhaled asbestos fibers. Asbestosis causes progressive shortness of breath, persistent cough, and reduced lung function. It does not improve with treatment, and it is a recognized basis for compensation under most trust schedules and civil claims.

Lung Cancer

Asbestos exposure significantly increases the risk of lung cancer, particularly when combined with a history of smoking. Asbestos-related lung cancer is compensable under the same trust schedules and civil claim avenues as mesothelioma.

Other Recognized Diseases

Pleural plaques, pleural thickening, laryngeal cancer, ovarian cancer, and certain gastrointestinal cancers are also recognized as asbestos-related under various trust schedules and case-law authorities, though eligibility and proof requirements vary by claim type.

If you have any of these diagnoses and you worked at this facility, lived with someone who did, or were exposed in any documented capacity, you may have a claim worth pursuing. Speak with an attorney before assuming you don't qualify.

Cross-State & Regional Corridor Workers

Like many industrial facilities and power plants along the Mississippi River industrial corridor, including Labadie Energy Center or Portage des Sioux Power Plant in Missouri, or Granite City Steel in Illinois, constructed before the 1980s, the Thomas Hill Energy Center reportedly contained asbestos-containing materials (ACMs). These cases are often pursued in St. Louis City Circuit Court in Missouri, or in plaintiff-friendly venues like Madison County, Illinois, or St. Clair County, Illinois, especially for workers along the shared industrial corridor. If you or a family member worked at the Thomas Hill Energy Center in Clifton Hill, MO, or other regional facilities like Granite City Steel / U.S. Steel, Laclede Steel, Monsanto Chemical, or the Shell Oil / Roxana Refinery in Illinois, and received a diagnosis of mesothelioma, asbestosis, or another asbestos-related disease, seek legal advice immediately.

Data Sources

Information about facility equipment, industrial materials, and occupational records referenced on this page is drawn from publicly available sources where applicable, including:

If specific equipment or product claims in this article are sourced from a non-public database, the source is identified parenthetically within the text above.