Class Code 4498
Plastics – Injection Molded Products Mfg
Class Code 4498 covers manufacturers that produce parts and products by injection molding thermoplastic and thermoset resins. This classification applies to the full press operation and common secondary work done in the same facility. The September 1, 2026 approved pure premium rate for California is $5.348 per $100 of payroll, which informs baseline workers' comp cost for these operations.
What Class Code 4498 Covers
This code applies to facilities that melt plastic pellets or regrind, inject the molten polymer into steel molds under pressure, cool and eject finished parts, and perform routine secondary operations such as trimming, de-gating, inspection and light assembly when done by the same workforce. It includes manual and automated injection molding machines, hot runners and mold temperature controllers, part conveyors, robotic pick-and-place tending, and in-plant mold maintenance and adjustments. Raw material handling (pellet bags, regrind loading), colorant blending, and use of mold release agents are typical activities included when integral to production. Tool rooms that exclusively perform heavy tool and die manufacturing for outside customers may be treated separately; however routine mold repairs done as part of the molding operation fall under this classification.
Who It Applies To
- Injection-molding machine operators and press tenders
- Mold setters, mold maintenance technicians, and mold repair staff
- Robotic cell operators and automation technicians used for part removal and stacking
- Quality inspectors and dimensional measurement technicians working on molded parts
- Secondary operations workers doing trimming, de-gating, assembly, or packaging in the same plant
- Material handlers who load resin, colorants, and handle regrind within the molding area
Common Job Duties
- Setting up and operating injection molding presses (adjust temperatures, pressures, cycle times)
- Installing, aligning, and changing molds; performing minor mold repairs and maintenance
- Loading resin hoppers and handling bulk bags or boxes of pellets and regrind
- Tending automated cells and programming or supervising robot pick-and-place systems
- Trimming, de-gating, sanding or machining flash from molded parts and performing visual/measurement inspection
- Cleaning hot runners, applying mold release agents, and performing housekeeping in molding cells
Common Injury Risks
Understanding the $5.348 Rate
The pure premium rate of $5.348 per $100 of payroll is the WCIRB-approved baseline for expected loss costs in this classification and is multiplied by an employer's payroll to determine the pure loss portion of premium. Insurance companies then apply experience modification factors, policy-level schedule credits or debits, and expense/loadings to produce the final premium an employer pays. Employer-specific factors—such as loss history, safety programs, claims frequency/severity, payroll mix, and classification accuracy—can materially raise or lower the actual premium.
Cal/OSHA Compliance Requirements
Cal/OSHA compliance for injection molding centers focuses on machine guarding and control of hazardous energy (lockout/tagout) to prevent crush and amputation hazards during mold changes and servicing. Hazard Communication (GHS) and respiratory protection standards apply where workers are exposed to monomers, solvents or aerosols from mold release agents; local exhaust ventilation is often required for enclosed drying hoppers, hot runner vents and secondary operations. Employers must also address PPE, noise monitoring/hearing conservation, and training/documentation for confined-space entry if silos or large resin storage vessels are present.
How Key HR Helps Employers Under Class Code 4498
A PEO like Key HR can reduce workers' comp cost drivers for injection molding shops by centralizing claims management, obtaining favorable group purchasing power, and enforcing best-practice safety programs targeted to molding hazards (machine guarding audits, lockout/tagout procedures, heat/burn prevention, and respirator/HazCom programs). Key HR also supports return-to-work and light-duty plans, OSHA recordkeeping, on-site or virtual training tailored to mold changeover and press operation, and regular risk assessments to lower frequency and severity of claims.
Get a QuoteFrequently Asked Questions
Does Class Code 4498 include mold maintenance and tool repair?
Routine mold maintenance, minor repairs and adjustments performed in the molding area are included in 4498 because they are integral to production. Heavy tool and die work done in a separate tool room for outside customers may be classified differently; report those operations separately to your insurer to ensure correct coding.
What practical steps lower workers' comp costs for injection molding operations?
Key steps include implementing robust machine guarding and lockout/tagout, scheduled preventive maintenance for presses and hot runners, local exhaust ventilation for fume sources, targeted PPE and training, ergonomic aids for mold handling, and an active return-to-work program to reduce indemnity claim duration.
Are secondary operations such as trimming and assembly covered by this code?
Minor secondary operations performed by the same employees on the production line—trimming, de-gating, inspection and light assembly—are typically included in 4498. If your facility has a large separate assembly operation with different hazards, that work may require a different classification; review duties and payroll allocation with Key HR during quoting.
Quick Facts
- Class Code
- 4498
- Classification
- Plastics – Injection Molded Products Mfg
- Pure Premium Rate
- $5.348 / $100 payroll
- Effective Date
- September 1, 2026
- Source
- WCIRB Approved Filing
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