Bag Houses & Flue Gas Scrubbers — Asbestos Exposure Crosswalk
What This Equipment Is
Bag houses and flue-gas scrubbers are large air-pollution-control (APC) systems installed downstream of boilers, kilns, smelters, and other combustion sources. They serve different functions:
- Bag houses capture particulate by filtering flue gas through arrays of long fabric bags suspended in compartments. Periodically the bags are cleaned by reverse pulse, mechanical shaking, or reverse-flow gas.
- Wet scrubbers capture SO₂, acid gases, and fine particulate by spraying flue gas with absorbent liquid (typically lime / limestone slurry for SO₂ removal). The reacted liquid drains out as a slurry; the cleaned gas continues to the stack.
Both systems are large, hot, and heavily insulated. They are gasketed extensively, use fabric expansion joints between ductwork sections, and (in the bag-house case) historically used some asbestos-fiber-bearing filter media in selected high-temperature applications.
Asbestos Products Historically Used Around APC Systems
| Product Category | Where on the System | Notes |
|---|---|---|
| Block insulation | Bag-house casing, scrubber vessel exterior | Calcium silicate, magnesia |
| Pipe / duct covering | Inlet and outlet ductwork | Block insulation, pipe covering |
| Fabric expansion joints | Inlet, outlet, intermediate ductwork | Asbestos cloth — see Expansion Joints |
| Gaskets | Bag-house access doors, hopper flanges, scrubber recycle piping | Asbestos sheet gasket material |
| Filter media (historical) | Selected high-temperature bag-house applications | Asbestos-fiber-bearing bag filter material in specific eras |
| Valve packing | Slurry isolation, recycle, drain valves | Braided asbestos rope packing |
| Insulating cement | Joints and irregular surfaces | Mixed dry, hand-applied |
Why APC System Work Was a High-Exposure Activity
Bag-house and scrubber installations on existing power plants (the large 1970s–2000s scrubber-retrofit wave) required substantial new ductwork construction, modifications to existing breechings (see Breechings), and insulation of the new vessels. The construction phase generated heavy fresh-insulation exposure for the trades involved.
Operational maintenance — bag changes, hopper cleanout, scrubber-nozzle replacement, recycle-line repair — disturbs casing insulation and gaskets repeatedly across the equipment’s service life.
Manufacturers Named in Litigation Involving These Products
- Research-Cottrell — APC OEM named in installation/maintenance claims
- American Air Filter / AAF — APC OEM
- Wheelabrator-Frye — APC OEM
- Joy Manufacturing — APC OEM
- Babcock & Wilcox — APC products
- Combustion Engineering — APC products
- Johns-Manville — block insulation, duct covering, filter media in certain applications
- Owens-Corning / Fibreboard — block insulation
- Garlock Sealing Technologies — fabric expansion joints, gaskets
Documented Product References
Images sourced from publicly available product-identification reference materials. Inclusion does not constitute a finding of liability against any company.
Trust Funds That May Apply
- Babcock & Wilcox Company Asbestos PI Trust
- Combustion Engineering 524(g) Asbestos PI Trust
- Manville Personal Injury Settlement Trust
- Owens-Corning / Fibreboard Asbestos PI Trust
- Garlock Sealing Technologies LLC Asbestos PI Trust
Trades Most Exposed at APC Work
Insulators (Heat & Frost), boilermakers, iron workers and welders on ductwork construction, sheet-metal mechanics, refractory masons, contract construction crews on scrubber retrofits.
Jobsites in the Network
- Every coal- or oil-fired Missouri power plant with APC retrofits in the network
- See companion pages: Boilers, Breechings, Precipitators, Expansion Joints
Compiled from publicly filed asbestos litigation, EPA / state-DNR records, and industry-publication histories. Product and company references reflect what has been alleged or documented in publicly filed litigation. This page does not constitute a finding of liability against any company. Not legal advice; consult a licensed attorney about your specific situation.