Coker Units (Delayed Coker) — Asbestos Exposure Crosswalk
What This Equipment Is
A delayed coker is a refinery upgrading unit that converts heavy vacuum residue (“bottom of the barrel”) into petroleum coke, gas oils, and lighter products. The unit operates as a semi-batch process: feed is heated in a charge heater (see Fired Heaters) and routed to one of two or more large coke drums, where it cracks and deposits as petroleum coke on the drum walls. When a drum fills with coke, feed switches to a parallel drum while the full drum is cooled, drained, and cut out with high-pressure water.
The coke drums are tall (up to 100+ feet) and large (up to 30+ feet in diameter), running at coking temperature (~900–950°F). They cycle between coking, cooling, and decoking on roughly 18- to 24-hour intervals.
Asbestos Products Historically Used Around Coker Units
| Product Category | Where on the Coker | Notes |
|---|---|---|
| Block insulation | Coke-drum shells (full height) | Calcium silicate, magnesia |
| Pipe covering | Charge-heater outlet, drum-overhead, switch-valve manifolds | Magnesia, calcium silicate |
| Charge-heater refractory | Heater interior | See Fired Heaters and Refractory Mortar |
| Switch-valve packing | High-temperature double-block-and-bleed valves | Braided asbestos rope packing |
| Gaskets | Manway covers, switch-valve flanges, blind-flange isolation | Asbestos sheet, spiral-wound |
| Cutting-water-system gaskets | High-pressure decoking system | Asbestos sheet gasket material |
Why Coker Work Was a High-Exposure Activity
Coker maintenance is unusually intense because of the thermal cycling. Coke drums cycle from coking temperature to ambient and back every 18–24 hours, which destroys gaskets and embrittles insulation faster than steady-state equipment. Switch-valve rebuilds, drum-head gasket replacements, and insulation patches are recurring maintenance items. Major turnarounds rebuild the entire system including charge heater (refractory rip-out and reline) and switch-valve overhaul. Cleaning out failed drums — extreme cases where coke didn’t drain — was historically extremely dangerous high-exposure work.
Manufacturers Named in Litigation Involving Coker Components
- Foster Wheeler — coker licensor and equipment
- Conoco / Conoco Engineering — coker technology
- Lummus — coker technology
- A.P. Green Refractories — charge-heater refractory
- Harbison-Walker Refractories — refractory
- Johns-Manville — block insulation, pipe covering
- Owens-Corning / Fibreboard — insulation
- Garlock Sealing Technologies — gaskets
- A.W. Chesterton — packing
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
- Manville Personal Injury Settlement Trust
- Owens-Corning / Fibreboard Asbestos PI Trust
- Garlock Sealing Technologies LLC Asbestos PI Trust
Trades Most Exposed at Coker Work
Pipefitters, boilermakers, refractory masons, insulators (Heat & Frost), iron workers, refinery turnaround contract crews, plant operators handling the decoking cycle.
Jobsites in the Network
- Missouri refineries running delayed coker units
- See companion pages: Fired Heaters, Distillation Towers, Cat Cracker
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.