Class Code 4771
Explosive Mfg; Rocket Propellant Mfg
Class Code 4771 covers manufacturers who formulate, process, assemble, test and store explosive materials and rocket propellants. This work carries a high pure premium rate of $1.192 per $100 of payroll, reflecting the elevated severity and frequency of potential losses.
What Class Code 4771 Covers
This classification applies to facilities that manufacture explosive compounds, solid or liquid rocket propellants, motor grains, and related energetic materials. Operations include chemical formulation and weighing of oxidizers and binders, milling or micronizing energetic powders, solvent casting or extrusion of propellant grains, curing and post-cure machining of motor components, motor assembly and static testing, plus on-site storage in magazines and packaging for shipment. The code covers both pilot-plant/lab-scale propellant development and full production lines when the employer performs manufacturing rather than purely R&D. Support functions that directly handle or move explosive materials—material handlers, forklift operators, and maintenance staff who enter processing areas—are typically included under this classification.
Who It Applies To
- Aerospace propulsion manufacturers producing solid rocket motors or propellant grains
- Defense and munitions plants formulating or assembling energetic charges
- Commercial pyrotechnic and specialty explosive product manufacturers
- Contract research labs and pilot plants developing rocket propellants
- On-site production facilities for propellant grains and motor assembly
Common Job Duties
- Weighing, batching and mixing oxidizers, fuels, binders and plasticizers
- Milling, micronizing and handling fine energetic powders under dust-control systems
- Casting, extruding, curing and machining propellant grains and motor components
- Filling, drying and solvent-removal operations with explosive-laden solvents
- Assembling motor casings, igniters and safety devices; static testing of motors
- Loading/unloading and inventory control in secured magazines and transport packaging
Common Injury Risks
Understanding the $1.192 Rate
The approved pure premium rate of $1.192 per $100 of payroll represents the insurer's expected cost of claims for this class, before expense loads and adjustments. Employers calculate the pure premium by multiplying payroll (divided by 100) by 1.192; the final premium an employer pays also includes insurer expense loadings, experience modification, schedule credits/debits, policy limits, and any deductible or retrospective rating plan.
Cal/OSHA Compliance Requirements
California employers manufacturing explosives and propellants must comply with Cal/OSHA safety orders including Process Safety Management principles, Hazard Communication, respiratory protection, and confined-space and hot-work controls under Title 8 general industry requirements. Facilities also must coordinate with local fire marshals and comply with state and federal regulations for magazine storage, transportation (DOT), and licensing/registration where applicable; written programs, employee training, emergency response plans and thorough recordkeeping are essential.
How Key HR Helps Employers Under Class Code 4771
A PEO like Key HR can help manufacturers reduce workers' comp exposure by implementing industry-specific safety programs, administering Process Safety Management and Hazard Communication plans, coordinating specialized training, and managing claims and return-to-work programs to reduce lost-time. We also consolidate payroll reporting, help lower experience modification impact through proactive loss control, and provide access to carriers experienced in high-hazard accounts.
Get a QuoteFrequently Asked Questions
Does small-batch experimental propellant work belong in Class Code 4771?
Yes. Even pilot-plant or R&D activities that involve formulation, mixing, casting or static testing of energetic propellants are normally classified in 4771 because the core exposure—handling energetic materials—is the same as production work.
What specific training will Cal/OSHA expect for workers in this class?
Training should cover hazard communication for energetic materials, safe handling and transfer procedures, explosion and fire prevention, respirator use and fit testing, emergency response and evacuation, hot-work permitting, and any site-specific Process Safety Management elements required by the facility.
How can I reduce my workers' comp premium for a propellant manufacturing operation?
Focus on measurable loss-control: documented PSM and HAZCOM programs, engineering controls (ventilation, dust suppression, inerting), scheduled preventive maintenance, qualified hot-work permitting, rigorous PPE and respiratory programs, and a return-to-work plan to limit lost-time claims. Partnering with a PEO or specialty carrier to standardize these controls and manage claims can lower experience modification and overall premium.
Quick Facts
- Class Code
- 4771
- Classification
- Explosive Mfg; Rocket Propellant Mfg
- Pure Premium Rate
- $1.192 / $100 payroll
- Effective Date
- September 1, 2026
- Source
- WCIRB Approved Filing
Manage Workers' Comp Through a PEO
Key HR provides pay-as-you-go workers' comp for California employers — no large deposits, no audits, better rates.
Get a Quoteor call (800) 922-4133Ready to Simplify Workers' Comp for Class Code 4771?
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