Understanding the Workplace »: Enclosed and Hazardous Areas

Figure 1. Danger of carbon monoxide poisoning in confined spaces.
Figure 1. Danger of carbon monoxide poisoning in confined spaces.

Only designated types of forklifts can be used in certain hazardous locations in the workplace.

Figure 2. Posted chemical hazard area.

Be familiar with OSHA's truck designations and hazardous location classifications. Only use powered industrial trucks that have the correct designation for the location's classification. Post signs in hazardous areas. [29 CFR 1910.178(c)]

OSHA Powered Industrial Truck Designations

The OSHA standard specifies 11 designations of powered industrial trucks [29 CFR 1910.178(b)]:

  1. D. Diesel powered units with minimal acceptable safeguards against inherent fire hazards.

  2. DS. Diesel powered units with additional safeguards to the exhaust, fuel, and electrical systems.

  3. DY. Diesel powered units that have all the safeguards of DS units, plus do not have any electrical equipment including the ignition. They have temperature limitation features.

  4. E. Electrically powered units with minimal acceptable safeguards against inherent fire hazards.

  5. ES. Electrically powered units with additional safeguards to the electrical system to prevent emission of hazardous sparks and to limit surface temperatures.

  6. EE. Electrically powered units that have all the safeguards of the E and ES units, plus the electric motor and all other electrical equipment are completely enclosed.

  7. EX. Electrically powered units with electrical fittings and equipment designed, constructed, and assembled so that the units can be used in certain atmospheres containing flammable vapors or dusts.

  8. G. Gasoline powered units with minimal acceptable safeguards against inherent fire hazards.

  9. GS. Gasoline powered units with additional safeguards to the exhaust, fuel, and electrical systems.

  10. LP. Liquefied petroleum gas units with minimal acceptable safeguards against inherent fire hazards.

  11. LPS. Liquefied petroleum gas units with additional safeguards to the exhaust, fuel, and electrical systems.

Designated Locations

The OSHA standard [29 CFR 1910.178(c)], see Table N-1] provides a listing of classified locations where trucks with each type of designation can operate.

When used indoors, forklifts powered with internal combustion engines can present indoor air quality hazards. Cold weather, with the closing of doors and windows, may increase the risk.

Potential Hazard

  • Concentration of fumes.

Requirements and Recommended Practices

  • Do not operate a gasoline/propane/diesel engine for long periods of time in a confined area, such as a truck trailer

  • Shut the engine off when staying inside a small confined area like a trailer.

  • Do not operate a combustion engine within a warehouse, plant or onboard ship without adequate ventilation.

  • Be careful in cold weather. Doors and windows which are normally open may be closed and exhaust and other gases may concentrate.

  • Be careful in small rooms or blocked off areas where gases may accumulate.

  • Drive sensibly. Avoid racing the engine or idling for long periods of time.

  • Properly maintain engines and do not operate an engine requiring servicing. [29 CFR 1910.178(p)(1)]

  • Consider switching to battery-powered forklifts, if much of the work is in poorly ventilated spaces or operators may be over-exposed to exhaust byproducts.

  • Consider upgrading the ventilation system.

  • Install CO monitors to detect levels.

Figure 3. Powered industrial truck engaged in roll-on roll-off (Ro-Ro) operations and subject to 29 CFR 1915.12.

Note: Special Precautions Onboard Ship

If the space to be entered contains an oxygen deficient atmosphere, the space shall be labeled "Not Safe for Workers" or, if oxygen-enriched, "Not Safe for Workers - Not Safe for Hot Work." If an oxygen-deficient or oxygen-enriched atmosphere is found, ventilation shall be provided at volumes and flow rates sufficient to ensure that the oxygen content is maintained at or above 19.5 percent and below 22.0 percent by volume. The warning label may be removed when the oxygen content is equal to or greater than 19.5 and less than 22.0 percent by volume. [29 CFR 1915.12(a)(2)]

For additional information, see the Materials Handling: Hoisting and Hauling Equipment module of the Shipyard Employment eTool.

Figure 4. Danger of carbon monoxide poisoning in confined spaces.

Forklifts powered with internal combustion engines can cause high levels of carbon monoxide in enclosed work areas.

Potential Hazards:

  • Unconsciousness and death may result from carbon monoxide overexposure as the concentration in the bloodstream rises.

Requirements and Recommended Practices:

  • Train employees to recognize the warning signs of excessive exposure.

  • Learn to recognize the symptoms and signs of carbon monoxide overexposure.

  • Be especially aware of the dangers onboard ship. [29 CFR 1915.12]