Press Operators

Press operators ran the compression molding, transfer molding, and injection molding presses that produced thermoset plastic parts during the asbestos era. In smaller shops, the press operator and the molder were the same person. In larger operations, press operators specialized in running and maintaining specific press lines while material handlers loaded compound.

What the job involved

A press operator’s responsibilities included:

  • Setting up and changing molds — physical handling of mold tooling, often with residual cured compound and asbestos dust attached
  • Operating the press cycle — closing, applying heat/pressure, opening, ejecting parts
  • Adjusting cure times, temperatures, and pressures — based on compound type and part specifications
  • Inspecting parts as they came off the press — close-range examination of freshly molded asbestos-containing parts
  • Cleaning the press between runs — removing cured compound residue from mold faces, ejector pins, and press surfaces

Specific press types

Asbestos-phenolic compounds were processed in three main press types during the era:

  • Compression molding — the most common type for asbestos-phenolic. Granules loaded into open mold, press closes and cures.
  • Transfer molding — compound loaded into a “transfer pot” that pushes the heated material through runners into the mold. Used for parts with inserts.
  • Injection molding (less common for thermosets) — heated compound injected from a barrel into the closed mold

Each press type involved compound handling, heat/pressure cycling, and finished part removal — with characteristic exposure patterns for each.

Exposure pathways unique to press operators

Beyond the compound handling exposures shared with molders, press operators experienced:

  • Mold cleaning — using rags, scrapers, and sometimes compressed air to clean mold faces between cycles. Compressed-air cleaning was a known major exposure source.
  • Press maintenance — opening press components for repair, exposing accumulated dust
  • Tool changeover — physical handling of cured-compound-encrusted tooling

Plants where press operators worked

Press operators were employed at the same compound-manufacturer plants and downstream molding shops as molders (see the Molders page for site list).

If you (or a family member) worked this occupation

Free, confidential case evaluation: Speak with O’Brien Law Firm — (314) 936-2956

Most workers in these occupations did not know that the “plastic” they handled contained asbestos. The compound manufacturers and downstream molding shops are documented in publicly filed litigation. Trust-fund claims and civil lawsuits can both be pursued — see the Trust Funds page for the compensation pathways.

References to manufacturers, products, and exposure intensities reflect what has been alleged or documented in publicly filed asbestos litigation, NIOSH and OSHA measurements, and industry archives.