New test to prevent industrial asthma

Research from the UK has indicated that spray painters can develop industrial asthma at a rate 80 times higher than the general public. In response to this alarming statistic, SafeWork NSW has been looking into spray painting in the motor vehicle repair industry. Over a two year period SafeWork inspectors investigated risks to health and safety as well as how to improve harm prevention. They also launched an Australian first – a new urine test to monitor exposure to harmful urethanes.

It’s believed that hardener, one of the components in two pack urethane paint, contains a known respiratory sensitising agent, isocyanate, or more correctly monomeric isocyanate. In recent years, paint manufacturers have reduced the quantity of free monomeric isocyanate in paint products, but with cases of industrial asthma persisting, additional testing and research is required to understand where exposure is occurring and how to combat it.

The project involved:

  • urine testing to determine spray painter exposure to various isocyanates present in the hardener of urethane paints. The urine test was developed by TestSafe, SafeWork’s Thornleigh Laboratory.
  • testing spray painters’ overall solvent exposure by looking at urine for either solvents or solvent metabolites
  • determining compliance levels of spray painting booths in accordance with the Australian Standards and relevant codes of practice
  • re-familiarising SafeWork inspectors with the hazards associated with the motor vehicle repair industry and in particular, looking into the hazards around spray painting.

TestSafe’s urine test for isocyanate exposure is the first such test in Australia. It is a major advance in safety for people who work with isocyanates. Previously, a sick patient was all a doctor had to determine exposure, so by the time respiratory changes were picked up it was usually too late to reverse the patient’s asthma. However, as the test is so new it is not yet widely known in the motor vehicle repair industry or amongst general practitioners. SafeWork plans to increase knowledge around the availability of the urine test and its harm prevention applications in monitoring exposure levels and avoiding respiratory diseases.

Exposure levels

During the project, the isocyanate urine test was offered to spray painters at no cost to the business. Two hundred spray painters from 78 businesses submitted urine samples. Of these, five showed exposure to isocyanates and two yielded high exposure levels, one of which measured up to the current exposure limit and the other more than twice the limit. Exposures to toluene (a solvent often found in paint thinners) showed three workers over the exposure limit. Testing for other solvents or their metabolites was all below the exposure threshold. The good news is that there were less people with high exposure levels than in previous studies. This might be explained by the increasing use of water based paints in the industry.

Other hazards

In conjunction with creating general knowledge around the urine test, SafeWork inspectors were tasked with ensuring spray painting booths met the requirements of the Australian Standards and were maintained in accordance with best practice.

The relevant standards are: AS/NZS 4114.1:2003 Spray painting booths, designated spray painting areas and paint mixing rooms – design, construction and testing and AS/NZS 4114.2:2003 Spray painting booths, designated spray painting areas and paint mixing rooms – installation and maintenance, as well as the Code of Practice: Spray painting and powder coating – 2015.

Given the motor vehicle repair industry is the biggest urethane paint user; this industry was the main target for the project, which also looked at other hazards associated with spray painting. These included dangerous goods storage; correctly using and storing personal protective equipment (PPE); consistent health monitoring for spray painters; electrical safety; plant safety; noise; and hazardous manual tasks. SafeWork involved specialist business areas such as the Dangerous Goods, Ergonomics, Plant and Electrical Safety Teams to provide expert advice and training to the various regional offices that were part of the project.

Additional findings

SafeWork visited 340 motor vehicle repair businesses across NSW during this project and found compliance was low at 38 per cent. Inspectors issued a total of 760 improvement notices for spray booths but only four prohibition notices for plant and electrical. The main reasons for improvement notices were spray booth maintenance, electrical, plant, PPE, dangerous goods storage and chemical registers. By the end of the project all 340 businesses had achieved 100 per cent compliance. When it came to booths and PPE, the majority of spray painters did not wear +ve pressure air supplied respirators and if they did, failed to have a separate airline supplying the respirator mask as required by the Australian Standard. A number of spray booths inspected (+ve) were found to leak paint spray into the immediate environment around the spray booth. Finally, a survey of 10 paint mixing areas showed solvent vapours never came within the lower explosive limit.


  • Spray painters should take regular urine tests to monitor chemical exposure levels.
  • Use isocyanate-free coat lacquers where possible as this will significantly improve the health of spray painters and eliminate any inadvertent exposures to others in the industry.
  • Spray booth operators should use water based paints even if the final clear coat still contains isocyanates.
  • Air supplied respirators of the positive pressure kind should be considered against alternatives on the market such as powered air purifying respirators.
  • Paint mixing rooms/areas should have good ventilation and all electrical appliances and switches should be raised appropriately above the mixing table in case of a thinners spillage.
  • Electrical switches for equipment leads in paint mixing rooms should be elevated well above the mixing table to avoid the solvent vapours which are heavier than air and sit lower.
  • Electrical equipment such as scales and colour matching machines should be raised above the bench on non-flammable plinths to avoid the possibility of a major solvent spill on the mixing bench.
  • The need for interlocks on the booth doors could be reconsidered but the airflow/heater interlock must remain.
  • If there is cracked glass over the booth illumination lights and it is not severely broken, it can be taped up with clear tape and replaced when the booth filters are replaced.

If you would like more information on SafeWork NSW’s spray painting project or safety in the motor vehicle repair industry, call 13 10 50 or visit

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