- Service Unit Operators, Oil, Gas, and Mining
- Stationary Engineers and Boiler Operators
- Chemical Plant and System Operators
- Gas Plant Operators
- Petroleum Pump System Operators, Refinery Operators, and Gaugers
- Separating, Filtering, Clarifying, Precipitating, and Still Machine Setters, Operators, and Tenders Green
- Cooling and Freezing Equipment Operators and Tenders
- Pump Operators, Except Wellhead Pumpers
- Wellhead Pumpers
- Tank Car, Truck, and Ship Loaders