Rollers and paintbrushes are common for home projects, but they’re rare in industry. Spraying is a much more efficient way to cover large areas in a short period of time without sacrificing quality.
But spray painting has its own risks, and it’s critical that workers who perform spray painting and coating tasks understand the hazards involved and how to control them.
What Are Spray Painting and Powder Coating?
Spray painting is the process of applying liquid paint using pressure. This can be done in one of three ways:
- Conventional high-pressure spraying
- Airless spraying
- High-volume low-pressure (HVLP) spraying
Conventional High-Pressure Spray Painting
This method uses an air compressor and an air gun. When the gun’s trigger is pressed, the paint mixes with the compressed air stream and a fine spray is released from the nozzle.
The air gun is usually held about 6 to 10 inches from the object being painted and moved back and forth over the surface to ensure an even and continuous coat.
Airless Spraying Systems
These systems use a high-pressure pump, which can range in pressure from just 300 to 7,500 pounds per square inch, depending on the application.
With this method, the pressurized paint container pushes the paint to the nozzle, where it is atomized by the spray gun.
These are similar to conventional spraying systems, but they use a higher volume and lower pressure. This ensures that more paint or coating ends up on the surface and less of it gets dispersed into the air.
While each of these methods is slightly different, they all achieve the same end goal. And they all have similar hazards that must be accounted for.
Practically speaking, hazards from paint and coatings can be found in almost industry where they are used. But there are a handful that use spray paints and coatings far more frequently than others, and where workers are at an increased risk, including:
- Auto body shops
- Sign painting shops
- Furniture, door, and appliance manufacturing facilities
- Metal fabrication shops that manufacture and repair oilfield equipment, heavy machinery, and transportation equipment
- Shipbuilding facilities
- Sandblasting and coating facilities
There are two categories of concern for workers using paint and coatings. First, the paint or coating product itself, and second, the application process. It’s important for every employer to conduct a safety assessment to identify the specific risks their workers face.
Exposure to Hazardous Substances
Though the use of highly toxic chemicals in paint and coatings is less prevalent now than in decades past, workers can still become exposed to compounds in excessive concentrations. Some paints and coatings, moreover, contain isocyanates, which are powerful sensitizers that can cause negative health effects through inhalation or dermal contact.
Exposure tends to occur when particles become airborne, which is why workers who use spray painting methods are at a higher risk for illness than those who use brushes and rollers. But workers can also be exposed to hazardous chemicals at any stage of the spray painting process, including preparation (preparing surfaces or tinting and pouring paint), storage, clean up, and disposal.
Hazardous chemicals that workers may be exposed to include:
- Paint strippers
- Surface preparation products
- Rust removers
Vapor exposure risks are of particular concern for workers in confined spaces, such as those spraying inside the cavity of vehicles, ships, aircrafts, or tanks. Workers in these spaces must take proper precautions to ensure their work area is well ventilated and use the right PPE for the situation.
Workers exposed to hazardous vapors may experience symptoms soon after, which include headaches, nausea or vomiting, dizziness, and irritation to the nose, throat, and lungs.
Long-term health effects that may not be recognized as quickly can include:
- Kidney or liver damage
- Respiratory illness
- Damage to the reproductive and central nervous system
Fire and Explosion
The solvents used in paint and coats are typically flammable or combustible. While simply handling them poses a risk to workers, spray applications multiply that risk due to the generation of aerosols and vapors.
The vapors from spray painting spread quickly – especially in a confined space – resulting in a potentially explosive atmosphere. This mist coming into contact with an ignition source could result in an explosion that doesn’t just put the workers in the immediate workspace in danger, but also others in the building and nearby area.
Potential risks include:
- Serious burns
- Exposure to projectiles
- Property damage
One of the less recognized hazard to employees conducting spray painting work is the physical toll it takes on them. The overexertion, repetitive movements, and sustained awkward postures that can come from long periods of spray painting can cause muscle strain. It’s important that workers take breaks as needed and request assistance to access hard-to-reach places.
Controlling the Risks
There are a variety of ways employers and workers can help manage the hazards associated with spray painting and coating.
Wherever possible, eliminating the hazards by using different materials or a different process is the best way to control risk. You can do this by:
- Using water-based materials in place of toxic, solvent-based ones
- Using a brush or roller instead of a spray gun
- Using low-hazard products, including cleaning solvents
Isolating the Hazard
Using a spray booth ensures that workers in the surrounding area are not affected by the airborne paint. It also helps contain any vapors that could cause a fire or explosion.
Engineering controls like ventilation systems can reduce the presence of vapors in the work atmosphere and minimize worker exposure to potentially hazardous fumes.
Administrative controls can complement engineering ones and further reduce the risk. Restricting employee access to areas where spray painting is being carried out, for example, can help prevent other employees from inadvertently becoming exposed.
Personal Protective Equipment
Proper PPE is essential to protect worker health. For employees involved in spray painting operations, this should include:
- Eye protection
While much of the safety focus is on the potentially harmful substances being sprayed, it’s important to consider the spraying equipment as well. Conduct regular preventative maintenance to ensure that spray guns and other related equipment are working as they are supposed to.
Equipment that doesn’t seem to be functioning properly should be removed from service until it can be inspected more thoroughly.
Of course, OSHA also mandates that employers take specific action to mitigate the risks involved with spray painting and coating work. It’s important that both employers and workers get familiar with some of the key standards to ensure a safe work atmosphere for everyone.
Equipment and PPE
- When PPE is used, employers must conduct a hazard assessment of tasks and justify their selection of appropriate protective equipment
- Workers’ faces, eyes, heads, hands, and all other exposed parts must be protected during the handling of highly volatile paints
- All footwear must be non-sparking (e.g. rubber); outer clothing should be cotton; rubber gloves should be used in place of plastic ones
- Workers’ eyes must be protected during spray painting; acceptable PPE includes safety goggles, full-face respirators, and loose-fitting hood respirators
- Respirators must be used during spraying operations in confined spaces with toxic solvents; the air must be tested and deemed suitable for human consumption
- Workers doing exterior spraying with toxic paints must be protected by filter cartridge type respirators
- Only non-sparking spray guns may be used
Engineering and Administrative Controls
- Sufficient exhaust ventilation must be provided to keep solvent vapor concentration below 10 percent of the lower explosive limit
- Ventilation must be continued after painting until the space is free of gas
- No matches, lighted cigarettes, cigars, or pipes, and no cigarette lighters or ferrous articles may be taken into the area where work is being done
It’s not always feasible to use a roller or paintbrush to complete a job. But even when spray painting or coating is necessary, there are numerous steps workers and their employers can take to ensure the work is carried out safely. Educating workers about potential hazards and mitigating the risks are crucial components of a job well done.