Isocyanate (2-pack) paints

Exposure to Isocyanate in paint can cause long-term and sometimes life-threatening illness.

Spray mist containing isocyanate may cause or worsen existing asthma. Once people are affected even very low exposure levels can trigger an attack.

Significant skin contact with isocyanate hardeners may cause dermatitis.

Vehicle paint spraying and occupational asthma

Paints containing isocyanate are used extensively in MVR. Isocyanates are found in most vehicle coatings even in some ‘water-based' paints. Remember, 'water-based' does not necessarily mean 'isocyanate-free'. Spraying produces the highest exposures and is the main cause of occupational asthma. MVR paint sprayers have an 80 times higher risk of getting asthma compared with the UK working population. Every year over 50 sprayers are diagnosed with isocyanate asthma and most have to leave the industry. Below are some key tips for vehicle paint sprayers and owners of motor vehicle repair bodyshops.

Vehicle paint sprayers

• The risk of developing occupational asthma occurs because paint spraying produces a lot of invisible airborne mist that you can breathe in. Never spray paint outside the booth or room.
• Your booth/room takes time to clear of mist, so know the clearance time and make sure everyone else does too.
• Always wear air-fed breathing apparatus (BA) when spraying and know how to safely leave or enter your booth or room during the clearance time.
• Your employer should check the controls are working by measuring your exposure to isocyanate. Currently the only way to do this is by providing a urine sample for analysis. See Sector Information Minute 3/2008/11 Controlling isocyanate exposure in MVR - the role of biological monitoring
• You need regular health surveillance i.e. lung function testing and skin checks.

Bodyshop owners / managers

• Spraying 2-pack isocyanate paints creates fine, invisible, airborne mist that can cause occupational asthma
• It spreads through the air like smoke.
• Your spray booth or room takes time to clear of fine paint mist.
• Measure the clearance time using a smoke/fog generator, clearly mark it on the entrance door(s) and make sure everyone who uses the booth/room knows what to do. For information on smoke generators and advice on how to conduct a clearance time measurement please see 'Measuring paint spray booth clearance time'.
• The research report 'An automated system for indicating spray clearance times of MVR spray booths and rooms - RR742' describes the design and assembly of a device consisting of a timer switch, programmed with the clearance time, which is triggered by a sensor that detects when the spray gun is turned on and off. Two types of sensor are evaluated and recommendations made for different operational setups. The system is relatively inexpensive and can be retrofitted to existing spray booths/rooms.
• Make sure the booth or room runs at slight negative pressure so that it cannot leak fine mist during spraying
• Make a list of simple daily and weekly checks to be done in the booth/room, appoint someone to do them, record the findings and act if things are wrong
• Check exposure is properly controlled by arranging for the analysis of urine samples of vehicle paint sprayers.
• Arrange regular health surveillance for those potentially exposed to isocyanate paints such as sprayers. For more information on health surveillance for occupational asthma see HSE guidance publication 'Health surveillance for occupational asthma (G402)'
• Use the e-COSHH essentials guidance sheets and other published advice to help you reduce exposures to isocyanates.

Further information

• Example risk assessment for a motor vehicle repair body shop
• From experience - case study
• Ten bodyshop myths that can take your breath away
• COSHH essentials guidance sheets on the safe use of isocyanates in MVR
• Safety in MVR; working with 2-pack isocyanate paints INDG388 (2003)
• Motor vehicle repair: Good practice for SMART (small and medium-area repair technique) sprayers WEB33
• Controlling isocyanate exposure in spray booths and spray rooms (WEB36)
• Measuring paint spray booth clearance time
• Visiting premises spraying isocyanate-based paints: A checklist for HSE staff
  This guidance will give you an idea of what Health and Safety Awareness Officers from HSE will be looking for if they visit your bodyshop.
• Reducing ill health in the motor vehicle repair industry – developing issues SIM 3/06/04
• MVR topic inspection pack – Isocyanate exposure
  Topic inspection packs describe and support the duties of HSE inspectors.
• An automated system for indicating spray clearance times of MVR spray booths and rooms - RR742
• HSE Asthma website