Class Code 4740
Oil Refining – Petroleum; Asphalt/Tar Distilling/Refining; Gasoline Recovery
Class Code 4740 covers oil and petroleum refining operations including asphalt and tar distilling and gasoline recovery. The WCIRB pure premium for California effective Sept 1, 2026 is $1.316 per $100 of payroll. Employers in this sector must manage high-hazard process risks, rigorous Cal/OSHA rules, and turnover during turnarounds — all of which affect workers' comp exposure.
What Class Code 4740 Covers
This classification applies to facilities that refine crude petroleum into finished fuels and petroleum products, operate asphalt or tar distillation units, or run gasoline recovery and vapor-recovery systems. It includes continuous refinery operations (distillation columns, cokers, catalytic crackers), heat-treating and furnace operations, tank farms and product blending, and on-site gasoline recovery/degassing processes. The code covers both routine production staff and those performing scheduled shutdowns, turnarounds, or maintenance that expose workers to refinery process hazards. Activities such as sampling, lab testing of petroleum streams, treating and storage of heavy residuals (asphalt/tar), and operation of recovery vapor condensers are within scope. It does not typically cover downstream retail gasoline stations or long-haul tank truck transport, which are usually classified separately.
Who It Applies To
- Refinery process operators and control room technicians
- Maintenance mechanics and turnaround craft crews (welders, fitters)
- Tank farm operators and product blending personnel
- Asphalt/tar distillation plant operators and laboratory staff
- Gasoline recovery and vapor control system technicians
Common Job Duties
- Operating and monitoring distillation columns, furnaces and fractionators
- Sampling and laboratory analysis of crude and product streams
- Inspecting, repairing and replacing valves, exchangers and piping
- Performing hot work (welding, cutting) during maintenance and turnarounds
- Loading/unloading and gauging storage tanks and product transfer lines
- Maintaining vapor recovery systems, condensers and flare systems
- Entering and working in permit-required confined spaces (tanks, vessels)
Common Injury Risks
Understanding the $1.316 Rate
The pure premium of $1.316 per $100 of payroll is the portion of premium intended to pay expected claim costs before insurer expenses and profit. Carriers multiply that rate by an employer's payroll (in $100 units), then apply experience modification, schedule credits/debits, policy-level deductible or retrospectives, and insurer expense loads to produce the final premium. Loss frequency, severity, turnaround schedules, and safety programs materially influence an employer's experience modification and final premium.
Cal/OSHA Compliance Requirements
Refinery operations are subject to Cal/OSHA process safety requirements (refinery PSM), permit-required confined space rules, hazardous materials communication and respiratory protection standards, and hot work and fire prevention controls. Employers must implement written PSM-type management systems, lockout/tagout, written confined space entry programs, and documented hazard communication and respiratory-protection programs, plus maintain training and records for inspections and audits.
How Key HR Helps Employers Under Class Code 4740
A PEO like Key HR can centralize workers' comp coverage and provide sector-specific loss-control resources: refinery-tailored safety programs, permit and hot-work procedure templates, confined-space and H2S training, and coordinated claims management to reduce indemnity and medical costs. Key HR also helps monitor experience modification, manage return-to-work programs, and leverage purchasing scale to stabilize premiums for employers in high-hazard coding like 4740.
Get a QuoteFrequently Asked Questions
Does Class Code 4740 include contractors working on refinery turnarounds?
Yes, payroll for contractors that are on your payroll and performing refinery operations or maintenance at the site is typically reported under the refinery class. Independent subcontractors paid separately are usually outside your payroll reporting; proper contract wording and classification audits are important to avoid coverage disputes.
What practical steps lower workers' comp costs for 4740 operations?
Focus on reducing claim frequency and severity: rigorous permit-required confined-space programs, hot-work controls, PSM-style management of change and pre-job hazard analyses, mandatory PPE and respiratory protection, proactive medical monitoring (for benzene/H2S), and a formal post-injury return-to-work program to shorten lost-time exposure and improve your experience modification.
Are gasoline terminals or tank truck loading operations included in this class?
Not usually. Bulk terminals, tanker-truck loading/unloading, and retail fuel operations are commonly assigned different WCIRB classifications. If your operation combines refining with terminaling or transport, a classification review is recommended to ensure payroll is assigned correctly.
Quick Facts
- Class Code
- 4740
- Classification
- Oil Refining – Petroleum; Asphalt/Tar Distilling/Refining; Gasoline Recovery
- Pure Premium Rate
- $1.316 / $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 4740?
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