De-Aerators — Asbestos Exposure Crosswalk
What This Equipment Is
A de-aerator is a pressure vessel between the low-pressure and high-pressure feedwater heaters in a steam plant. Its job is to strip dissolved oxygen and carbon dioxide from feedwater before that water reaches the boiler — without it, dissolved gases would aggressively corrode boiler tubes. The de-aerator uses scrubbing steam to “deaerate” the water by raising it to saturation temperature in a packed tray section and venting the released gases.
De-aerators are typically horizontal cylindrical pressure vessels mounted high in the boilerhouse, with a feedwater storage section directly below. The entire assembly runs at saturation temperature corresponding to its operating pressure (typically 5–15 psig), so the shell and the storage tank are heavily insulated.
Asbestos Products Historically Used Around De-Aerators
| Product Category | Where on the De-Aerator | Notes |
|---|---|---|
| Block insulation | Vessel shell and storage tank exterior | Calcium silicate, magnesia |
| Pipe covering | Steam supply, vent, condensate, and feedwater lines | Magnesia, calcium silicate |
| Gaskets | Manway covers, vent flanges, level-instrument connections | Asbestos sheet gasket material |
| Valve packing | Vent valves, level controls | Braided asbestos rope packing |
| Insulating cement | Joints and irregular surfaces | Mixed dry, hand-applied |
Why De-Aerator Work Was an Asbestos Exposure Pathway
De-aerator internals (trays, scrubbers) wear and foul over time and require periodic inspection and replacement. Manway access during outages exposes maintenance crews to legacy fiber when insulation is stripped to permit access. Vent-piping freeze damage in cold-climate plants is a recurring repair item that disturbs insulation each time.
Manufacturers Named in Litigation Involving These Products
- Johns-Manville — pipe covering, block insulation
- Owens-Corning / Fibreboard — pipe covering, block insulation
- Armstrong World Industries — calcium silicate insulation
- Garlock Sealing Technologies — gaskets
- Crane Co. — valves
- Cochrane Corporation — de-aerator OEM named in installation claims
- Graver Tank — de-aerator OEM
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
- Manville Personal Injury Settlement Trust
- Owens-Corning / Fibreboard Asbestos PI Trust
- Garlock Sealing Technologies LLC Asbestos PI Trust
Trades Most Exposed at De-Aerator Work
Pipefitters, insulators (Heat & Frost), boilermakers, maintenance mechanics.
Jobsites in the Network
- Every Missouri power plant in the network
- See companion pages: Boilers, Feedwater Heaters, Block Insulation
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.