Electrical apparatus was the largest single application for asbestos-filled phenolic compound, and the reason is physical rather than commercial. A device that interrupts current under load has to do three things at once inside a moulded plastic housing: insulate at high voltage, hold its dimensions while the surrounding metal expands and contracts, and survive the arc — a momentary plasma that can exceed the melting point of steel. Asbestos fibre in a phenolic binder did all three, and until glass and mineral-fibre reformulations matured in the 1970s there was no equally cheap substitute.
The consequence is that the compound is concentrated in exactly the components a working electrician touches most: the breaker, the arc chute, the panel interior, the starter.
Circuit breakers and breaker housings
The moulded case, the arc chamber and the internal barriers of a breaker were routine asbestos-phenolic applications. Publicly filed litigation records describe the following manufacturers as consumers of asbestos-containing phenolic compound for breaker production:
- General Electric — circuit breakers and breaker housings. GE is described in these records as using asbestos-filled phenolic compounds through approximately 1977, at a peak of roughly 60 million pounds per year across its plants and product lines.
- Cutler-Hammer — circuit breakers and enclosed circuit breakers, alleged in publicly filed records to run from the 1930s through the mid-1970s. Eaton Corporation acquired Cutler-Hammer in 1978 and is the active defendant for these claims.
- Square D — circuit breakers, with the Lexington, Kentucky plant specifically named in publicly filed asbestos litigation. Now Schneider Electric.
- Federal Pacific Electric — breaker housings, described as the plastic enclosures and arc chambers of the Stab-Lok and other FPE breaker lines, made at 150 Avenue L, Newark, New Jersey.
A note on Stab-Lok: that product line is separately and widely known in product-liability litigation for alleged safety defects. The asbestos question here is a different one. It concerns the phenolic compound used to mould the housings, and it is a worker-exposure claim rather than a product-failure claim.
Switchgear — arc chutes and phase barriers
The arc chute is the component that takes the arc directly, and it is the single most consistently documented asbestos-phenolic part in the electrical record. Alongside it sit phase barriers, arc runners and the insulating shields that separate energised phases inside a switchgear cubicle.
Named in publicly filed records for switchgear applications: General Electric (arc chutes and phase barriers explicitly), Westinghouse, Cutler-Hammer (panelboards and switchgear), Square D (switches and switchgear components), and Federal Pacific Electric (plastic components in distribution switchgear).
Arc chutes matter disproportionately for exposure because of what maintenance does to them. An arc chute is a wear part. It is pulled, inspected, scraped clean of arc products and replaced on a maintenance cycle — work that is abrasive, performed in a confined cubicle, and repeated across a career.
Panelboards, load centers and bus hardware
Inside the panel, the moulded parts are the bus supports and covers, the neutral assemblies, the trim and the insulating barriers. Federal Pacific Electric is described in publicly filed records as using asbestos-phenolic compound for panelboard and load-center components including bus covers, neutral assemblies and trim pieces; Cutler-Hammer and Square D are named for panelboards.
This is the category most likely to reach a person who never worked in manufacturing at all. Panel interiors are opened, modified, extended and re-trimmed in the field for the entire service life of a building.
Motor starters, contactors and relays
Control gear carried the same requirements as breakers in a smaller package — arc containment plus structural insulation.
- Cutler-Hammer — industrial motor starters and contactors, described as a high-volume consumer of asbestos-phenolic compound given the scale of its electrical-control manufacturing.
- Square D — motor starters and contactors, and motors for electrical panel boxes and transformers at the Lexington, Kentucky plant.
- Allen-Bradley — electrical control enclosures, relay housings and motor-starter components at its Milwaukee, Wisconsin operations. Allen-Bradley both consumed compound and manufactured it, under the Rostone brand. Union Carbide deposition testimony in publicly filed records identifies Allen-Bradley as a company Union Carbide “tried to get business from” for Bakelite phenolic compound. Now Rockwell Automation.
Transformer components
General Electric is named for transformer components, and Square D’s Lexington plant for motors serving transformers. Westinghouse Micarta appears here in its laminate form rather than as a moulded part — as insulating barriers, spacers, terminal boards and coil-end insulation cut and fitted into transformer assemblies.
Micarta — the grade problem in miniature
Westinghouse Micarta is the clearest illustration of why brand-level identification is not enough. Micarta was made with paper, cotton, linen, glass and asbestos reinforcement, in both laminated sheet and moulded forms. Publicly filed trial records and alleged expert testimony identify specific grades as asbestos-containing:
| Grade | As described in publicly filed records |
|---|---|
| Grade 102 Molded Micarta | “the only asbestos-containing molded Micarta product manufactured after 1949” |
| Moldarta 162, 170, 180 | “short asbestos fiber as the filler material bound in phenolic resin” |
| Moldarta 164, 166 | similar in construction to grade 102 |
| Sheet / tubing | Westinghouse file numbers 44141 AA-AE, 44141 AF-AK, tubing 44141 PA; related Material Card 42331 AA-AC Rev 2 / 2118 |
Two people who both “worked with Micarta” may have entirely different exposure histories depending on the grade. The grade designation, not the brand, is what carries the answer.
Who supplied whom
Publicly filed records include a Reichhold Chemicals interrogatory naming the electrical manufacturers to whom Reichhold is alleged to have supplied asbestos-containing phenolic moulding compound:
Cutler-Hammer · Allen-Bradley (Rostone) · Allis-Chalmers · Ward Leonard · General Electric · Square D · Westinghouse
That single document connects a compound supplier to seven electrical-equipment manufacturers at once, which is why supplier interrogatories carry weight disproportionate to their length. It is an allegation in a litigation record, not an established finding.
The people downstream
The workers named on this site’s occupations pages — compounders, molders, press operators — handled the material in bulk and carry the heaviest exposure. But the finished apparatus went on to be installed, maintained and torn out by a much larger population:
- Electricians and IBEW members, racking and pulling breakers, changing arc chutes, trimming panels
- Industrial and plant maintenance workers, on switchgear and motor-control centers
- Navy and merchant sailors, around shipboard switchboards, controllers and distribution panels in confined machinery spaces
- Powerhouse and utility workers, on substation and generating-station switchgear
- Demolition and renovation trades, breaking out old panels and gear during building work
Exposure in these roles comes from disturbance rather than manufacture — filing, sanding, drilling, scraping arc products, cutting laminate, and breaking apart old components. Intact, sealed phenolic is not the concern; the dust released when it is worked is.
Identifying a part
If you are trying to work out whether a specific piece of apparatus contained asbestos-phenolic components, the details that carry the most weight are:
- Manufacturer and product line — and, where visible, the grade or file number moulded or stamped on the part
- Date of manufacture, not date of installation. Apparatus stayed in service for decades; a 1968 breaker found in a 1995 renovation is a 1968 exposure question
- Whether the work disturbed the material — cutting, sanding, filing, drilling, or scraping, as against simply being near an intact part
- A MIL-M-14 type designation, if present, given that 12 of the 20 defined compound types were mineral-filled
These are the same questions a lawyer and an industrial hygienist would ask. This page cannot answer them for any individual part — it sets out what publicly filed records describe, so the right questions can be asked of the right documents.
Everything above is drawn from publicly filed litigation records and alleged witness testimony. Grade designations, customer lists and date windows appear in those records as allegations and testimony rather than as established findings. Product lines frequently included both asbestos-filled and asbestos-free grades.