Airborne particles and vapors, heat, noise, hazards from falling objects, working at height, and chemical contact are examples of hazards that workers may be exposed to during painting and coating operations. And these are just a few examples when it comes to potential hazards during painting and coating in metalworking and heavy manufacturing industries.
This blog will review some of the more common hazards encountered during painting and coating applications in metalworking and heavy manufacturing industries. These hazards include inhalation of vapors and particles, skin and eye injuries, and harmful noise exposure. We will also explore specific groups of chemicals painters may use and some important health and safety measures that can be taken to help protect these workers and others who may be exposed in these industries.
What Types of Noise Hazards Exist when Painting and Coating?
Exposure to loud noise is one of the most widespread hazards for people working in metalworking and heavy manufacturing and many other industries. Occupational noise exposure is the second most common risk factor in the workplace, and one of the most commonly reported occupational illness in many countries.
In fact, according to the World Health Organization, it is estimated that 430 million people worldwide have disabling hearing loss, and on average, about 16% of adult-onset hearing loss is due to occupational exposure. The global cost of unaddressed hearing loss is estimated at $980 billion/year, and noise is now being acknowledged as an important public health issue and a top environmental risk faced by the world today.[i]
Unlike many other workplace injuries or illnesses, the symptoms of overexposure to noise are often unnoticed until significant exposure has occurred and permanent damage to the hearing system has been done. There is no blood or visible damage and seldom any pain to warn people that there is a problem. Additionally, damage to the hearing system can occur slowly over time and the early warning signs are easy to miss.
Noise exposure levels during painting and coating applications in metalworking and heavy manufacturing vary widely and are influenced by the specific industry, surrounding environment, application process, and spray equipment used. The range is quite large, from as low as 60 decibels to as high as 107 decibels. This broad range is due to a variety of factors including the method of application and spray equipment used and background noise from ventilation systems and other work being conducted in the area.
What Eye and Face Hazards Should You be Concerned About During Painting and Coating Applications?
Eye and face injuries are another hazard found in painting and coating applications. The eye is a critical organ that many of us easily overlook when it comes to protection. Prevent Blindness America estimates that “eye injuries of all types occur at a rate of more than 2,000 per day. Of these, 10% to 20% will be disabling because of temporary vision loss.” It is also estimated that 90% of these injuries could have been prevented had the worker been wearing eye protection or wearing the appropriate kind of protection for the tasks being performed.
The source of these hazards can be paint mist and vapors, contact with powder or liquid paints and coatings, foreign bodies, and high velocity particles from compressed air and paint guns to the eyes and face.[ii] According to the US Bureau of Labor Statistics approximately 31% of all eye injuries in the U.S. are due to impact from flying objects or particles, and approximately 26% are due to foreign bodies in the eye.
Foreign body eye injuries can be a concern during painting and coating activities. Mists and fine suspended particles in the air can cause irritation, inflammation, and other damage. Liquids can be splashed, sprayed, or get into the eye. The eye can become inflamed, painful, and teary in reaction to the foreign object. Medical attention may be required to remove the foreign object, to wash out the eye, assess damage and apply treatment as required. In addition to foreign bodies, gases and vapors can also cause irritation, inflammation, and other damage.[iii]
What Respiratory Hazards Should Workers Take into Account While Painting and Coating?
Inhalation exposures will vary depending on the coating system applied and method of applications and can include a mixture of particles and gases and vapors
For example, airborne particles, including dust and mist, are formed when liquid coatings are aerosolized. Powder coating application also produces solid particles and dust.
Gases and vapors are formed as solvents in the liquid coatings evaporate. Vapors are also generated through handling and use of cleaning solvents and during paint mixing.
What Skin Hazards Can Workers Face while Painting and Coating?
Liquid contact to skin and eyes may occur if materials such as paints, primers, topcoats, and cleaning solvents are spilled or splashed. Contact with liquid and solid chemicals can often lead to various skin conditions or disorders. Depending on the chemicals involved, these can be due to both acute and chronic exposures such as:
- Irritant contact dermatitis, which is skin damage due to exposure to a physical or chemical agent, for example irritants such as organics solvents
- Allergic contact dermatitis where an allergic skin reaction is triggered by exposure to a substance, for example isocyanates.
Symptoms of irritant and allergic contact dermatitis can include itchy, blistered, dry, cracked, and discolored skin.
Specific examples of chemical agents that can cause skin disorders are isocyanates and epoxy resins that can cause an immune response and sensitization where even small quantities may be sufficient to cause an allergic reaction. Other examples are organic solvents which can remove oils and moisture from the outer layer or the skin. This can result in these solvents or other chemical irritants penetrating more deeply and causing further damage by triggering inflammation.
Irritant and allergic contact dermatitis may coexist, meaning a person may experience both of these skin disorders simultaneously.
What are Some Common Chemicals Used in Painting and Coating and the Health Hazards They Present?
Let’s take a look at some specific examples of chemicals that may be encountered during painting and coating applications.
Isocyanates are a wide and diverse range of highly reactive chemicals that are commonly used to react other organic molecules to create polyurethane polymers.[iv] Polyurethane polymers are highly durable, are both corrosion and ultraviolet (UV) resistant and are extensively used in paints and surface coatings.
Commonly used isocyanates include:
- Isophorone diisocyanate (IPDI)
- Methylene bisphenyl isocyanate (MDI)
- Toluene diisocyanate (TDI), and
- Hexamethylene diisocyanate (HDI/HMDI)
The main source of worker exposure is often from skin contact and inhalation of isocyanates, particularly when spray applying polyurethane paints, coatings, foams, glues and flooring compounds. Another significant source of potential exposure is the associated maintenance and cleaning of polyurethane coating spray equipment.
Acute overexposure to isocyanates can cause irritation of eyes, nose and throat, conjunctivitis, and skin irritation. Chronic or repeated overexposure can cause contact dermatitis, asthma, respiratory and skin sensitization, and liver and kidney dysfunction. Some agencies have classified toluene diisocyanate as a possible human carcinogen.[v]
Many different organic solvents are used in the painting and coating process, from cleaning solvents to solvents used in the paint and coating systems. Commonly used organic solvents include:
- Ethyl acetate
- Solvent mixtures such as white spirits
- Chlorinated solvents such as methylene chloride, trichloroethylene, and perchloroethylene
Adverse health effects due to overexposure can vary by individual solvent. Many organic solvents cause irritation to the skin and mucous membranes of the eyes and respiratory system. Organic solvents can also cause defatting of the fats and oils of the skin causing it to become dry, scaly, and irritated.
Inhalation of certain solvents can cause neurotoxic effects such as headaches, nausea, light-headedness, dizziness and in extreme cases unconsciousness and death.
Prolonged contact to certain organic solvents may result in allergic skin contact dermatitis.
Other organic compounds may be absorbed through the skin causing long term systemic effects to the liver, kidneys and heart.
Long-term inhalation of certain solvents can cause a range of neurotoxic effects including peripheral neuropathy which causes pain, numbness, tingling and weakness in hands, arms and feet; or neuropsychological effects such as fatigue, irritability, and altered mental state.[vi]
Hexavalent Chromium (Chromium 6)
Hexavalent chromium, also referred to as chromium 6, is a toxic form of chromium metal. Hexavalent chromium compounds are sometimes added to specialty paints and primers to provide corrosion protection and reflective properties. These chromium containing coatings are used primarily in aerospace and military applications.
Overexposure to hexavalent chromium can lead to a number of acute and chronic adverse health effects. Acute effects can include nose and respiratory tract irritation, skin irritation, inflammation, and ulceration, and eye irritation and damage. Chromic effects can include nasal ulcers, pneumonitis, respiratory and skin sensitization, kidney damage, fertility and development issues, and cancer.[vii]
Powder coating applications may expose painters to high levels of airborne particulate that can potentially lead to adverse health effects. These can include skin irritation, eye irritation as well as nose, throat, and respiratory tract irritation. Some powder coatings may contain hazardous pigments or hardeners, including lead chromate pigments, and triglycidyl isocyanurate or tri-mellitic anhydride hardeners. Overexposure to these hardeners can cause respiratory and skin sensitization, dermatitis, and asthma.[viii]
What Hierarchy of Control Measures Can be Taken to Help Protect Painters in Metalworking Industries?
Employers are required to assess the work environment to identify occupational hazards, and to implement measures to control these hazards and exposures. When controlling exposures to occupational hazards, employers should follow the Hierarchy of Controls. In order of effectiveness these controls are:
- Engineering controls
- Administrative controls, and
- Personal protective equipment (PPE).
When other controls are not effective or feasible, or when implementing other controls, PPE can be used to help reduce worker exposure. A wide variety of respirator options are available for painting and coating applications including half and full facepiece elastomeric respirators, powered air purifying respirators, and suppled air respirator systems. Certain powered and supplied air respirator systems feature headtops that combine head and face protection, providing integrated protection designed to perform as a single system. In addition, intrinsically safe powered air purifying respirators are available for use when spraying flammable or combustible coatings.
The amount of respiratory protection provided depends on the type of respirator. U.S. OSHA has Assigned Protection Factors (APF) for each type of respiratory protection. Protection factors range from 10 for a half facepiece respirator to 10,000 for a self-contained breathing apparatus. An exposure assessment must be conducted to determine the level of protection needed.
There is a wide variety of eye and face protection PPE available. Everything from safety glasses and goggles, safety glasses with a foam gasket, clear and tinted faceshields, and grinding and welding headtops with powered and supplied air respirator systems. It is important to select products that are appropriate for the hazard and working conditions and meet appropriate performance standards.
Where hearing protection is chosen as a control measure, there is a broad range of products to consider. Hearing protection covers a wide range of style, design and functionality.
Hearing protectors range from simple disposable foam plugs to the more sophisticated communication headsets with built-in Bluetooth functionality for two-way communication. Some earmuffs can be attached to industrial safety helmets or the rigid headtop of a powered & supplied air respirator system while others can be worn over-the-head or behind the head.
Protective coveralls are used to help protected workers from direct contact with paints and coatings during spray applications. This can include direct spray contact of liquids or deposition of liquid and solid overspray. Protective coveralls are manufactured from a wide variety of materials affording a wide variety of protection. At a minimum the type of protective coveralls selected should be based on specific garment performance characteristics, the type of coatings applied, the application method, and the amount of paint or coating contact anticipated.
It is critical to remember that no personal protective equipment does any good if it is not being worn. The time wearing the equipment, and wearing the equipment correctly, is imperative. PPE needs to be worn 100% of the time when exposed to hazards to be effective. For help selecting the right PPE given your painting and coating application, environment and needs, please do not hesitate to speak to our dedicated health and safety specialists today.
[i] World Report on Hearing, 2021 https://www.who.int/publications/i/item/world-report-on-hearing
[ii] Oxford Handbook of Occupational Health (2nd Edition)
[iii] Oxford Handbook of Occupational Health (2nd Edition)
[v] Smedley, J, Dick, F and Sadhra, S. Oxford Handbook of Occupational Health (second edition). 2013.
OSHA – Safety and Health Topics: Isocyanates, https://www.osha.gov/SLTC/isocyanates/
IARC Monographs on the Evaluation of the Carcinogenic Risk of Chemicals to Humans – Some Chemicals Used in Plastics and Elastomers, vol. 39, 1986
Isocyanates. Safe Work Australia – https://www.safeworkaustralia.gov.au/system/files/documents/1702/isocyanates_0.pdf
Isocyanates. OSHA – https://www.osha.gov/SLTC/isocyanates/
[vi] HSE INDG 273 – Working with solvents – A guide to safe working practices, https://www.hse.gov.uk/pubns/indg273.pdf
DHHS (NIOSH) Publication Number 87-104 – Organic Solvent Neurotoxicity, https://www.cdc.gov/niosh/docs/87-104/default.html
NIOSH – Organic Solvent Neurotoxicity https://www.cdc.gov/niosh/docs/87-104/default.html
CDC – Criteria for a Recommended Standard Occupational Exposure to Hexavalent Chromium https://www.cdc.gov/niosh/docs/2013-128/pdfs/2013_128.pdf
Smedley, J, Dick, F and Sadhra, S. Oxford Handbook of Occupational Health (second edition). 2013.
[viii] HSE – Reducing risks associated with using coating powders – employers, https://www.hse.gov.uk/surfaceengineering/reducing-risks-using-coating-powders-employers.htm
HSE – Working with coating powders – employees, https://www.hse.gov.uk/surfaceengineering/working-with-coating-powders-employees.htm