OSHA forklift classifications divide powered industrial trucks into seven classes under 29 CFR 1910.178, sorted by power source, how the operator rides or walks with the truck, and the surface the truck is built for. On top of those seven classes, OSHA assigns one of eleven separate designations (like D, EE, or EX) that control whether a specific truck can enter an area with flammable vapors, combustible dust, or other atmospheric hazards. The class tells you what kind of truck it is. The designation tells you where that truck is allowed to go.
How the Two-Layer System Works
The seven classes sort trucks by three characteristics: what powers them (electric motor or internal combustion engine), how the operator interacts with the truck (riding, walking, or standing), and where the truck belongs (smooth warehouse floors, narrow aisles, rough outdoor terrain). Classes I through III are all electric. Classes IV and V run on diesel, gasoline, or liquefied petroleum gas. Class VI includes both power types. Class VII covers rough terrain machines powered almost exclusively by combustion engines.1Occupational Safety and Health Administration. Powered Industrial Trucks (Forklift) – Types and Fundamentals – Types
Separate from the seven classes, every truck also carries one of eleven designations — D, DS, DY, E, ES, EE, EX, G, GS, LP, or LPS — reflecting spark protection, exhaust safeguarding, and temperature control built into the machine. These designations dictate which environments the truck may legally enter, including areas with flammable vapors, combustible dust, or ignitable fibers.2Occupational Safety and Health Administration. 29 CFR 1910.178 – Powered Industrial Trucks
Class I: Electric Motor Rider Trucks
Class I covers sit-down and stand-up rider trucks powered by electric motors. These are the workhorses of indoor warehousing: counterbalanced forklifts where the operator rides on the machine and steers with a traditional wheel. Because they produce no exhaust, they keep air quality safe in enclosed buildings without requiring the ventilation systems that combustion-engine trucks demand. Most facilities choose between cushion tires for smooth concrete floors and pneumatic tires for indoor surfaces that are slightly uneven or worn.
Electric power means batteries, and OSHA takes battery charging seriously. Charging stations must be in a designated area with ventilation strong enough to disperse hydrogen gas that batteries release while charging. The area needs fire protection equipment, supplies to flush and neutralize spilled battery acid, and material handling equipment like an overhead hoist for swapping heavy battery packs. Smoking, open flames, and anything that could spark are prohibited in charging areas.3eCFR. 29 CFR 1910.178 – Powered Industrial Trucks
Class II: Electric Motor Narrow Aisle Trucks
Class II trucks are built to work in tight spaces that would be impossible for a standard counterbalanced forklift. This category includes reach trucks, order pickers, and side-loaders — machines designed to operate in aisles far narrower than the roughly twelve-foot clearance that conventional rack layouts require.4Occupational Safety and Health Administration. Powered Industrial Trucks (Forklift) eTool – Understanding the Workplace – Narrow Aisles By stacking inventory higher and packing aisles closer together, facilities using Class II equipment can significantly increase storage capacity on the same floor space.
These trucks use electric power for the same air quality reasons as Class I, but the tighter environment amplifies the risk. Operators deal with limited visibility, loads lifted to significant heights, and steering controls that feel nothing like a standard forklift. A reach truck placing a pallet twenty feet up behaves very differently from one working at ground level, and stability at full extension is a real concern.5Occupational Safety and Health Administration. Powered Industrial Trucks (Forklift) – Training Assistance
Class III: Electric Motor Hand or Hand-Rider Trucks
Class III includes electric pallet jacks, walkie stackers, and similar equipment where the operator walks behind the truck or stands on a small built-in platform. A steering handle, not a wheel, controls direction and speed. These trucks handle shorter-distance tasks like moving pallets from a loading dock to staging areas or feeding product into larger storage systems.
People tend to underestimate Class III equipment because it looks simple. A loaded electric pallet jack can weigh several thousand pounds, and the operator is on foot right next to it. Crushing injuries to feet and legs are common when operators misjudge the truck’s momentum or lose control of the steering tiller. OSHA requires the same formal training and performance evaluation for Class III operators as for any other powered industrial truck.3eCFR. 29 CFR 1910.178 – Powered Industrial Trucks Pedestrian safety is also a bigger concern here, since these trucks operate in the same areas where people walk. OSHA guidance instructs operators to warn pedestrians and maintain safe clearance, and it requires permanent aisles to be kept free of obstructions and properly marked.6Occupational Safety and Health Administration. Powered Industrial Trucks (Forklift) – Understanding the Workplace – Pedestrian Traffic
Class IV: Internal Combustion Engine Trucks With Cushion Tires
Class IV trucks run on diesel, gasoline, or LP gas and ride on cushion tires, which are solid rubber with no air fill. The solid tire design gives them a lower profile and tighter turning radius than pneumatic-tire models, but it limits them to smooth, level surfaces like finished concrete. You’ll find these in warehouses and manufacturing plants where the floors are flat and the work demands more power than an electric truck delivers.
The tradeoff for combustion power indoors is exhaust. Carbon monoxide is the primary concern. OSHA’s permissible exposure limit for CO is 50 parts per million over an eight-hour shift, and a single propane forklift running in a poorly ventilated building can push concentrations above that threshold quickly. Employers using Class IV trucks indoors need to monitor air quality and ensure ventilation systems can handle the exhaust output.2Occupational Safety and Health Administration. 29 CFR 1910.178 – Powered Industrial Trucks
Class V: Internal Combustion Engine Trucks With Pneumatic Tires
Class V trucks share the same combustion power sources as Class IV but ride on pneumatic tires, either air-filled or solid-pneumatic, that can handle rough surfaces, gravel, and uneven ground. These are the trucks you see in lumberyards, outdoor storage areas, and loading docks where the terrain isn’t smooth enough for cushion tires. The traction and ground clearance make them capable of hauling heavy loads across surfaces that would destroy a cushion-tire machine.
Matching the right class to the right surface matters. Running a cushion-tire Class IV truck over rough terrain wears out the tires prematurely, reduces stability, and creates a real tip-over risk. OSHA requires that trucks be used only in environments matching their design, and the atmosphere must be evaluated for hazards before any powered truck enters the area.2Occupational Safety and Health Administration. 29 CFR 1910.178 – Powered Industrial Trucks Using a gasoline-powered truck in a location with flammable vapors without the correct designation is treated as a serious violation.
Class VI: Electric and Internal Combustion Engine Tractors
Class VI trucks are tow tractors. They pull trailers and carts rather than lifting or stacking pallets. You’ll see them in airports pulling baggage trains, in large manufacturing plants moving parts between buildings, and in distribution centers shuttling goods across long distances. This is the only classification that groups electric and combustion-powered units together, because the defining feature is the towing function rather than the power source.
The safety concerns here are different from lifting equipment. Drawbar pull capacity, braking systems capable of stopping a string of loaded trailers, and the wide turning radius of towed units are the primary focus. A tow tractor pulling four loaded carts through a facility with pedestrian traffic presents hazards that have nothing in common with operating a reach truck in a quiet aisle, and operator training must reflect that.5Occupational Safety and Health Administration. Powered Industrial Trucks (Forklift) – Training Assistance
Class VII: Rough Terrain Forklift Trucks
Class VII covers the heavy-duty machines built for construction sites, lumber yards, and anywhere the ground is uneven, muddy, or sloped. These trucks run on large tractor-like tires with high ground clearance and are powered almost exclusively by combustion engines for the torque needed to move loads uphill or across soft ground. Some use a vertical mast like a conventional forklift, while others have a telescopic boom that can extend forward and upward, useful for placing materials on rooftops or upper floors of buildings under construction.
Tip-overs are the biggest killer with Class VII equipment. Every forklift has what OSHA calls a stability triangle: an imaginary triangle formed by the two front wheels and the rear axle’s pivot point. As long as the combined center of gravity of the truck and its load stays inside that triangle, the truck remains stable. The moment it shifts outside, because the boom is extended too far, the load is too heavy, or the ground gives way on one side, the truck tips.7Occupational Safety and Health Administration. 29 CFR 1910.178 Appendix A – Stability of Powered Industrial Trucks On a construction site with slopes and soft soil, the margin for error shrinks considerably.
OSHA’s traveling rules require that loaded trucks ascending or descending grades steeper than 10 percent keep the load pointed uphill.3eCFR. 29 CFR 1910.178 – Powered Industrial Trucks Class VII operator training must address how the center of gravity shifts when a telescopic boom extends, how terrain slope affects lateral stability, and how to recognize ground conditions that can cause one wheel to sink.
The Eleven Hazardous Location Designations
The class number alone doesn’t tell you whether a truck can enter an area with flammable gases, combustible dust, or ignitable fibers. That’s what the designation letters are for. OSHA groups them by fuel type, with each family running from a base level of protection to progressively higher safeguards:
- D, DS, DY: Diesel-powered trucks. D has minimum safeguards. DS adds protection to the exhaust, fuel, and electrical systems. DY goes further, with no electrical equipment at all (including ignition) and temperature-limiting features.
- E, ES, EE, EX: Electric-powered trucks. E has minimum safeguards. ES adds spark prevention and surface temperature limits. EE fully encloses all motors and electrical components. EX is the highest tier, completely spark-proof, with bronze-banded chassis and forks that cannot create a spark even on contact with steel. Only EX trucks are approved for explosive atmospheres.
- G, GS: Gasoline-powered trucks. G has minimum safeguards. GS adds exhaust, fuel, and electrical system protections.
- LP, LPS: LP gas-powered trucks. LP has minimum safeguards. LPS adds exhaust, fuel, and electrical system protections.
The regulation maps each designation to specific hazardous location classes and groups. Some environments are so dangerous that no powered truck is allowed at all. OSHA prohibits all powered industrial trucks in atmospheres with hazardous concentrations of acetylene, hydrogen, ethylene oxide, or diethyl ether, among other substances. Locations with metal dust (aluminum, magnesium) or coal and coke dust allow only EX-rated trucks.2Occupational Safety and Health Administration. 29 CFR 1910.178 – Powered Industrial Trucks The employer must classify the atmosphere before selecting a truck for the area, not after.
Matching a Truck to Your Workplace
To pick the right truck, work through both layers in order. First, the class: electric or combustion power based on ventilation and indoor air quality; rider, walkie, narrow-aisle, tow tractor, or rough terrain based on the job; and cushion or pneumatic tires based on the surface. Second, the designation: evaluate the atmosphere for flammable vapors, dust, or fibers, and select a truck whose designation matches or exceeds the hazard level for that location.2Occupational Safety and Health Administration. 29 CFR 1910.178 – Powered Industrial Trucks
Skipping either step is where compliance breaks down. A Class IV cushion-tire truck is the wrong choice for a gravel lot even if the fuel type is fine, and a Class V pneumatic truck with a G designation is the wrong choice for a paint-spray area even if the terrain is fine. Both the class and the designation have to fit the workplace before the truck is put into service.