Portable generators supply electricity where none is available. They commonly are used following natural disasters and at construction sites. Portable generators produce electricity with an internal combustion engine that is run on a fuel source, usually gasoline, diesel, kerosene or propane. Although many construction sites are dependent on the electricity supplied by portable generators, their use increases the risk of injury. The Occupational Safety and Health Administration (OSHA) has identified four major sources of employee accident and injury associated with portable generators: carbon monoxide (CO) poisoning, fire hazards from improper refueling, improper storage hazards, and vibration and noise hazards.

It should be noted that, although electrocution and shocks are not specifically discussed, these hazards are present any time an employee works with an electrical system. The electricity provided by a generator is exactly the same as that supplied by normal utilities and has the same hazards, but generator use has additional hazards associated with it.

Generators often bypass safety devices typically built into electrical systems such as circuit breakers. Ground-fault circuit interrupters (GFCIs) should be used when using a generator. This is especially important when using electrical equipment in damp or wet locations.

Since a portable generator is a combustion engine, it gives off large amounts of carbon monoxide. This gas is colorless and odorless, making it extremely difficult to detect. Most people suffer from carbon monoxide poisoning without even realizing the gas might be an issue. This occurs mainly because the generator has not been properly ventilated.

The easiest way to ensure a generator is adequately ventilated is to never run it indoors or in any kind of enclosed space, including garages, basements or crawl spaces. A well-ventilated room will not prevent the buildup of the toxic gas. Portable generators are not designed to run indoors no matter how well ventilated the area. A generator should always be placed with 3–4 feet of clearance on all sides. This allows for air movement around the generator helping to increase ventilation and prevent CO buildup.

The best protection against CO poisoning is prevention. Recognizing the symptoms of CO poisoning is crucial. They include dizziness, nausea, headache and tiredness. If any employee shows any of these symptoms, they should get immediate medical attention. No one should re-enter the area until it has been determined to be safe by trained and properly equipped personnel. In many areas, the local fire department will help make this determination.

Under normal operating conditions, portable generators become quite hot, which increases the risk of fire while refueling. To prevent a fire, the generator must always be turned off and allowed to cool completely before refueling. Pouring a flammable liquid on hot engine parts can cause the fuel to ignite.

Another danger associated with portable generators has more to do with the fuel used to run them than with the generator itself. Where the fuel is stored can bring employees into harm’s way; flammable liquids should be handled and stored according to 29 CFR 1926.152. This includes ideas such as storing fuel outdoors in properly labeled containers away from the generator and any other heat source. The heat from the generator can cause fuel vapors to ignite even in a sealed container.

Vibration accidents and noise hazards are side effects of running a generator at a work site. Some generators can vibrate a great deal while running, possibly causing shifting and movement. If the generator is placed on uneven, unstable ground or on the tailgate of a truck, this shifting can cause the generator to tip over or fall off the truck. The resulting hazard involves both electrical and fuel dangers. If securing it in a truck bed is an option, it should be considered so as to avoid the possibility of the generator falling out of the truck. For those working near a generator, the noise level can be high enough to warrant hearing protection. The best way to determine if your company is using generators that require hearing protection is to check the owner’s manual and manufacturer’s specifications. Keep in mind that wearing hearing protection when it may not be required may help protect employees in the long run.

Portable generators are crucial to getting work done, and their use doesn’t have to be a hazard to employees. If a generator is treated with the respect that is typically given to utility-supplied electricity, the injuries to employees can be kept to a minimum.

KELLY is a safety and health specialist with Intec, a safety consulting, training and publishing firm that offers on-site assistance and produces manuals, training videos and software for contractors. She can be reached at 800.745.4818 or dkelly@intecweb.com. Joe O’Connor edited this article.