Product Description

Plastics Engineering Company (Plenco) manufactured Plenco 349 black as part of its line of asbestos-filled phenolic molding compounds. Phenolic resins — derived from the condensation of phenol and formaldehyde — served as the dominant thermoset matrix for electrical, automotive, appliance, and industrial parts through the 1940s–1970s asbestos era, valued for their dimensional stability, dielectric strength, heat resistance, and mechanical strength under load. Plastics Engineering Company (Plenco) of Sheboygan, Wisconsin manufactured Plenco 349 black, one of its asbestos-filled phenolic molding compound grades. Plenco 349 black was supplied in granular and powder form to custom phenolic molders for compression and transfer molding of electrical, automotive, appliance, and industrial parts during the asbestos era.

Documented Applications and Recipient Facilities

Plenco 349 black is documented in publicly filed Plastics Engineering Company answers to plaintiff interrogatories as supplied to the C.M. Moore Company / Majors Plastics, Inc. facility in Kansas City, Missouri in lot quantities ranging from 1,000 to 3,000 pounds across the 1961, 1962, and 1965 documented sales summaries. Plenco 349 black was also among Plenco’s general grades supplied to electrical equipment manufacturers including the Square D Company plants in the QO circuit breaker network (Cedar Rapids, IA; Columbia, MO; Lincoln, NE; Peru, IN; Lexington, KY). Plenco acquired the GE Genal phenolic molding compound business in 1982, further consolidating Plenco’s national phenolic supplier position.

Asbestos Content

Plenco 349 black is identified in publicly filed asbestos litigation records as an asbestos-filled phenolic molding compound, meaning asbestos fiber was an intentional and primary constituent of the product formulation rather than an incidental contaminant. The fiber loading in such compounds could constitute a substantial percentage of the product by weight, as the asbestos served multiple functional roles: reinforcing the resin matrix, improving tensile and flexural strength, extending heat resistance beyond what the unfilled resin could achieve, and providing dimensional stability during thermal cycling.

Once fully cured, phenolic molding compounds encapsulate the fiber within a hardened resin matrix. However, the bonded state of fibers in a finished molded part does not eliminate exposure risk across the full product lifecycle. Asbestos fibers in such materials become releasable during mechanical processing, machining, finishing operations, and whenever the cured part is cut, drilled, ground, or abraded.

How Workers Were Exposed

Litigation records document that industrial workers encountered Plenco 349 black and similar asbestos-filled phenolic compounds at multiple stages — from raw material handling through finished-part fabrication and downstream use:

  • Compound handling and hopper loading — transferring asbestos-filled phenolic compound from drums or bags into press hoppers; one of the highest-exposure tasks documented in phenolic molding operations
  • Compression and transfer press operation — hot molding releases compound dust when molds open between cycles
  • Tumbling, deflashing, and machining — finishing operations on cured phenolic parts release fiber from the matrix
  • Assembly and sub-assembly — fitting phenolic-molded components during switchgear and breaker build-up
  • Quality control and rework — disassembly during calibration and rebuild exposes workers to phenolic-part dust
  • Receiving, stockroom, and shipping — moving phenolic compound (drums, bags) and finished components

Documented Recipient Facilities

  • C.M. Moore Company / Majors Plastics, Inc. — Kansas City, Missouri (custom thermoset / phenolic compression molder; per Plenco discovery xlsx 1961–1965+)
  • Square D Company — Cedar Rapids, Iowa (QO breaker manufacturing)
  • Square D Company — Columbia, Missouri (1978+)
  • Square D Company — Lincoln, Nebraska (1971+)
  • Square D Company — Peru, Indiana
  • Square D Company — Lexington, Kentucky
  • Multiple downstream phenolic molders and electrical equipment manufacturers

Workers exposed to Plenco 349 black at any documented recipient facility — or to similar asbestos-filled phenolic compounds at downstream end-user facilities — may have legal rights if they have since been diagnosed with mesothelioma, asbestosis, lung cancer, or another asbestos-related disease. Asbestos-related diseases can develop silently for 20, 30, or even 40 years after initial exposure.

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