Toxicological hazards, their potential adverse outcomes
During the application of paint, workers are exposed primarily to solvents.
Exposure to workers can be by inhalation and via skin contact. It occurs specifically in operations that involve manual handling during preparation of the paint. Manual handling processes include weighing ingredients (pigments, extenders, resins, additives), loading them into mixing equipment, adding solvents to mills, cleaning equipment, thinning, tinting and shading, during filling operations, and during the filtering of varnishes. The cooking of varnishes may produce emissions of various aldehydes such as acrolein, ketones, glycerine and fatty acids as well as dusts or vapours of maleic, phthalic and fumaric anhydrides during the loading of kettles.
The production of powder coatings can be associated with significant exposure to dust from resin powders, pigments, curing agents and other additives. In the manufacture of radiation-curable coatings, exposures may occur to monomers such as ethyl acrylate, other acrylates, and photo-initiators. While inhalation and cutaneous contact are the major routes of exposure, ingestion related to personal work habits constitutes another potential route of entry.
Spray painting can cause short term health effects such as: irritation contact dermatitis, burns to the skin and eyes, vomiting, diarrhoea, headaches, dizziness, nausea, fatigue as well as irritation to the nose, throat and lungs.
Possible long term health effects that can result from spray painting can be: occupational asthma, allergic contact dermatitis, lung cancer, ‘painter’s syndrome’ (prolonged inhalation of paints and solvents resulting in brain damage), damage to the reproductive system as well as kidney or liver damage.
Possible short term health effects from inhalation and injection of spray painting can be: respiratory tract irritation, shortness of breath, dizziness, influenza-like symptoms, tightness of the chest, nausea and headaches.
Possible long term health effects from inhalation and injection of spray painting can be: cancer, sensitisation of respiratory systems, asthma, abnormal reduction in lung function, emphysema and central nervous system dysfunction.
Isocyanates are particularly hazardous and special care is required when dealing with products containing this chemical. Isocyanates are compounds containing one or more -N=C=O groups which can combine with other compounds containing alcohol groups. Isocyanates are commonly dissolved in aromatic solvents such as xylene and toluene, which in themselves are toxic. (National Occupational Health and Safety Commission, 1990)
There is sufficient evidence in humans for the carcinogenicity of occupational exposure as a painter. Occupational exposure as a painter causes mesothelioma, and cancers of the urinary bladder and lung. Also, a positive association has been observed between maternal exposure to painting (including pre-conception and during pregnancy) and childhood leukaemia in the offspring.
Recommendations regarding exposure assessment programs (e.g. basic strategy for exposure assessment)
Basic steps are required to be followed when assessing exposure in the workplace:
- Identify which workers are at risk of exposure
- Determine what sources and identify processes that are causing the risk
- Identify if and what kind of control measures should be implemented, and
- Check the effectiveness of existing control measures.
The following questions may help to assess the risk:
- How often, and for how long, will exposure to the hazard occur?
- In the event of exposure to the hazard, will the outcome be severe, moderate or mild?
- How do workers interact with the hazard (for example being exposed to hazardous chemicals by breathing it in or through skin contact)?
- Is there evidence of contamination (for example dust or fumes visible in the air, chemical odours, spills, splashes)?
- What are the conditions under which spray painting is carried out (for example confined space)?
- What are the skills, competence and experience of the operator?
Potential hazards may be identified in a number of different ways including:
- Conducting a walk through assessment of the workplace. During this assessment observation of the work practices and talking to workers about how work is carried out should take place.
- Inspecting the materials and equipment that will be used during the spray painting process. Assessing their suitability and toxicity.
- Reading product labels, SDS and manufacturer’s instruction manuals talking to manufacturers, suppliers, industry associations and health and safety specialists regarding the health hazards of use of different chemicals. Ensuring that the manufactures instructions are being followed.
- Reviewing incident reports to identify past hazard events and any related remedial action.
- Atmospheric monitoring to confirm that the environment is below the exposure standards and there is no risk to health.
- Health monitoring to identify bio-indicators for disease.
Spray booths should: be designed, constructed and installed to comply with AS/NZS 4114.1: Spray painting booths, designated spray painting areas and paint mixing rooms.
Spray booth ventilation control systems should operate a pre-purge cycle to remove any residue contaminants and also operate a minimum of a 5 minute post-purge period following spraying.
Ventilation systems should be capable of producing a minimum air movement of;
- 0.3 m/s for a full downdraft booth
- 0.4 m/s for electrostatic spraying
- 0.5 m/s for any other booth
Regulation 49 is taken from the Work Health and Safety Regulation 2011 relates to the need to provide a safe working environment.
Regulation 49: A person conducting a business or undertaking must ensure that no person at the workplace is exposed to a substance or mixture in an airborne concentration that exceeds the exposure standard for the substance or mixture.
Exposure standards represent the airborne concentration of a particular substance or mixture that must not be exceeded. There are three types of exposure standard:
- 8-hour time-weighted average
- peak limitation, and
- short term exposure limit.
Exposure standards are based on the airborne concentrations of individual substances that, according to current knowledge, should not cause adverse health effects nor cause undue discomfort to nearly all workers.
Regulation 50 is taken from the Work Health and Safety Regulation 2011 relates to the need to provide atmospheric monitoring to confirm that there is no risk to health.
Regulation 50: A person conducting a business or undertaking at a workplace must ensure that air monitoring is carried out to determine the airborne concentration of a substance or mixture at the workplace to which an exposure standard applies if:
- the person is not certain on reasonable grounds whether or not the airborne concentration of the substance or mixture at the workplace exceeds the relevant exposure standard; or
- monitoring is necessary to determine whether there is a risk to health.
The results of air monitoring must be recorded and kept for 30 years after the date the record is made.
Regulation 368 is taken from the Work Health and Safety Regulation 2011 and states the requirement for businesses to provide health monitoring to workers operating in high risk environments. A risk assessment of personnel in the facility would need to be conducted to identify the need for health monitoring. The risk assessment would need to take into account the tasks performed and chemicals used (in particular if it involves the use of isocyanates or lead). The health monitoring will involve a blood test (full blood count), and lung test (Spirometry) and urine test (solvent screen).
Regulation 368: A person conducting a business or undertaking must ensure health monitoring is provided to a worker carrying out work for the business or undertaking if:
- the worker is carrying out ongoing work at a workplace using, handling, generating or storing hazardous chemicals and there is a significant risk to the worker’s health because of exposure to a hazardous chemical referred to in Schedule 14, table 14.1, column 2, or
- the person identifies that because of ongoing work carried out by a worker using, handling, generating or storing hazardous chemicals there is a significant risk that the worker will be exposed to a hazardous chemical (other than a hazardous chemical referred to in Schedule 14, table 14.1) and either:
- valid techniques are available to detect the effect on the worker’s health, or
- a valid way of determining biological exposure to the hazardous chemical is available and it is uncertain, on reasonable grounds, whether the exposure to the hazardous chemical has resulted in the biological exposure standard being exceeded.
Prevention and/or Control Strategies.
Hierarchy of hazard control can be used to minimize or eliminate exposure to hazards.
- use a water-based paint instead of an organic solvent based coating
- use a brush or roller instead of a spray gun
- use a isocyanate-free products.
- use high volume low pressure (HVLP) spraying rather than airless spraying
- use a low hazard cleaning solvent
- Conduct all spray painting in a spray booth ensures that other workers are not affected by the spray painting.
Implementing engineering controls
- Use control measures such as ventilation systems including spray booths, to reduce exposure to vapours and aerosols.
- Computer-guided robots to undertake the spraying.
- Restricting access to spray painting areas or keeping the quantity of hazardous chemicals to minimum in the spray painting area.
- Provide relevant information, training, instruction or supervision to workers who are involved in spray painting or powder coating activities to enable them to carry out their work safely
- Ensure that the plant and equipment used in spray painting or powder coating activities is well maintained, operational and clean.
Any remaining risk must be minimised with suitable personal protective equipment (PPE), for example breathing protection, gloves, aprons and protective eyewear.
- Centers for Disease Control and Prevention . (2015 May). NIOSH Pocket Guide to Chemical Hazards. Retrieved 2015 June from http://www.cdc.gov/niosh/npg/
- Comcare. (2014 20-March). Spray painting. Retrieved 2015 7-June from Comcare: http://www.comcare.gov.au/Forms_and_Publications/publications/services/fact_sheets/fact_sheets/spray_painting/spray_painting2
- Safe Work Australia. (27/03/2015). Model Code of Practice – Spray painting/powder coating. Safe Work Australia.
- Work Health and Safety Regulations. (2011). Work Health and Safety Regulations. Canberra: Australian Government – ComLaw.