Blast Furnace Stoves & Hot-Blast Mains — Asbestos Exposure Crosswalk
What This Equipment Is
A blast furnace smelts iron ore to molten iron using coke (see Coke Ovens) and limestone as raw materials. The combustion air supplied to the furnace tuyeres must be preheated to 1,800–2,400°F by cowper stoves — large regenerative heat exchangers paired with the blast furnace. Stoves operate in cyclic mode: one stove is “on gas” (combusting blast-furnace gas to heat the internal checker brick), another is “on blast” (transferring stored heat to the combustion air on its way to the furnace).
The hot blast then travels from the stove through the hot-blast main — large-diameter refractory-lined steel pipe — to the bustle pipe ringing the blast furnace at tuyere elevation, then through individual tuyere stocks into the furnace.
Every component of this system runs above ambient and is refractory-lined inside, externally insulated, and gasketed. Asbestos-bearing products were specified throughout during the historical era.
Asbestos Products Historically Used Around Blast-Furnace Stoves
| Product Category | Where on the Stove System | Notes |
|---|---|---|
| Refractory brick / castable | Stove combustion chamber, checker work, hot-blast main, bustle pipe | See Refractory Brick |
| Block insulation | Stove shell exterior, hot-blast main jacket | Calcium silicate, magnesia |
| Pipe covering | Stove gas piping, cold-blast piping, by-product gas | Magnesia, calcium silicate |
| Gaskets | Stove valves, hot-blast main expansion-joint covers | Asbestos sheet, spiral-wound |
| Valve packing | Stove change-over valves, isolation valves | Braided asbestos rope packing |
| Asbestos cloth heat blankets | Around hot-blast main piping and valves | Asbestos cloth removable jackets |
| Insulating cement | Joints and irregular surfaces | Mixed dry, hand-applied |
Why Stove Work Was a Heavy-Exposure Activity
Stove re-bricking — replacement of the internal refractory after 15–25 years of service — is a multi-month capital outage employing dozens of refractory masons working inside the stove shell. Tear-out of legacy brick and back-up insulation generates dense dust at close range across the entire outage. Hot-blast main rebuilds during major blast furnace re-line projects similarly disturb extensive refractory and insulation.
Routine maintenance — stove valve rebuilds, expansion-joint replacements, leak repair — drives ongoing asbestos disturbance even between major outages.
Manufacturers Named in Litigation Involving These Products
- A.P. Green Refractories — refractory products
- Harbison-Walker Refractories — refractory products
- North American Refractories (NARCO) — refractory products
- General Refractories — refractory products
- Johns-Manville — block insulation, pipe covering, asbestos cloth
- Owens-Corning / Fibreboard — insulation
- Combustion Engineering — blast-furnace ancillary equipment
- Garlock Sealing Technologies — gaskets and expansion-joint cloth
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
- A.P. Green Industries Asbestos PI Settlement Trust
- Harbison-Walker Refractories / RHI Asbestos PI Trust
- North American Refractories Company (NARCO) Asbestos PI Settlement Trust
- General Refractories Asbestos PI Trust
- Manville Personal Injury Settlement Trust
- Owens-Corning / Fibreboard Asbestos PI Trust
- Combustion Engineering 524(g) Asbestos PI Trust
- Garlock Sealing Technologies LLC Asbestos PI Trust
Trades Most Exposed at Stove Work
Refractory masons (primary exposed trade), boilermakers, iron workers, pipefitters, insulators (Heat & Frost), contract blast-furnace rebuild crews, blast-furnace operators.
Jobsites in the Network
- Integrated steel mills across the state-site network
- See companion pages: Coke Ovens, Pouring Ladles, Hot Tops, Refractory Brick, Industrial Furnaces
Compiled from publicly filed asbestos litigation, OSHA / NIOSH / EPA records on steel-mill exposure, and academic epidemiology on integrated-steel-mill workers. 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.