By Safety Management Group

We use them around the house for everything from touching up patio furniture, to dusting furniture, to making the air (or people) smell better. You can find them on nearly every jobsite, in most work vehicles, and in offices. They’re small and easy to ignore. But when they explode or depressurize incorrectly, they can be deadly.

Since its introduction as a device for dispensing insecticides in the jungles of the Second World War, what was known then as a “bug bomb” and today as aerosol cans have become widely used devices for a broad variety of applications. They’re portable and disposable, making them very convenient. Most workers don’t think twice about using an aerosol can and tossing it aside when the task is complete or the can is empty.

Aerosol cans are normally manufactured from thin sheets of steel. The products they hold are highly pressurized with a number of types of hydrocarbon propellants, from carbon dioxide or butane or propane. In recent years, some scientists and environmental activists have linked chlorofluorocarbon (CFC) propellants to decreases in the planet’s ozone layer. Most manufacturers have shifted to propellants that are thought to be less damaging to the atmosphere.

Interestingly, most products sold in aerosol cans carry much higher costs by weight or volume than their non-aerosol counterparts. The propellant in an aerosol can may account for as much as 15 percent of the weight, and when you compare the cost of the remaining material (such as paint) with other delivery methods (such as paint sold in regular cans), you’ll see that using aerosols nearly always involves a significantly higher cost. 

Hazards to workers
Workers face three general types of hazards when working with aerosol cans. The first of these is the pressurization. As long as the can and the dispensing device remain intact, aerosol cans are safe. But any number of problems, such as a puncture, a faulty valve, excessive temperatures, or corrosion can result in unintended depressurization. In the most severe cases, aerosol cans may explode, burning nearby workers and showering them with steel shrapnel.

The second hazard is the actual product being dispensed by the can. Often, these products are inherently hazardous, such as in the case of insecticides. Others may contain hazardous substances, such as the concentrated solvents found in some paints or cleaners. In fact, some cans that are partially empty may be legally considered to be hazardous wastes. Finally, if either the propellant or the product it delivers is flammable, the aerosol can creates a fire hazard.

Safe work practices
As with most hazards, the first steps in reducing the dangers associated with aerosol cans is to determine whether they are really needed on the jobsite. If the task can be accomplished without the use of aerosol cars, workers will not have to contend with the hazards. Other forms of the material may be available. Or, refillable spray bottles or air-powered equipment may be available. 

If workers do use aerosol cans, they should be familiar with the Material Safety Data Sheets (MSDS) for the material and use the cans according to directions. Personal protective equipment or additional ventilation may be required.

Aerosol cans should always be stored in dry areas where they will not be exposed to excessive temperatures. As the temperature rises, pressure in the can will increase, and ambient temperatures about 120 degrees Fahrenheit may lead to explosions. Because car and truck interiors can become very hot in sunlight (even during the winter months), vehicles are generally not a safe location for even temporary storage.

Disposal issues
As noted earlier, leftover materials in partially filled cans may qualify as hazardous waste. If a can is found to be inoperative or malfunctioning, returning it to the supplier will prevent the user from having to treat it as hazardous waste.

Cans that are completely empty of both propellant and product are not considered to be hazardous waste, and may be recyclable. Companies that use a significant number of aerosol cans may wish to consider aerosol-puncturing equipment, which allows the contents of cans to be safely removed and prepared for disposal.

Aerosol cans should never be placed in fires or heated locations, because they may explode, and the propellant may be flammable. Cans that are still pressurized may also burst if place in a garbage compactor.

If cans that contain hazardous wastes are to be disposed, they should be placed in a special closed container displaying markings indicating that the waste is hazardous. The labeling should also indicate the specific types of waste and the date when the container began to be used. Keep records of when and how the waste was disposed or recycled.