• RCS

Working with 2-pack isocyanate paints

Updated: Apr 4


Paints containing isocyanate are used extensively in motor vehicle repair as almost all motor vehicle repair bodyshops use 2-pack or "2K" isocyanate-containing paints. Isocyanates are used in some water-based paints, most base coats and almost all lacquers. 'Water-based' does not mean 'isocyanate-free', just that it is emulsion based and has reduced levels of solvents.

Spraying 2-pack isocyanate paints is the main cause of occupational asthma in the UK and, for years, vehicle paint sprayers have been the group most at risk. MVR paint sprayers have about a 90 times higher risk of getting asthma compared with the UK working population. Every year around 50 sprayers are diagnosed with isocyanate asthma and most have to leave the industry. Other workers in bodyshops are also sometimes affected, e.g. maintenance personnel, managers and others who work in close proximity to spray booths/rooms. This spray mist containing isocyanate may also 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.

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 (and accepted by the MVR industry) is by providing a urine sample for analysis.

  • You need regular health surveillance, i.e. lung function testing and skin checks. This is to identify early symptoms and signs of occupational asthma and dermatitis (skin rashes).


Bodyshop owners / managers

  • Spraying 2-pack isocyanate paints creates fine, invisible, airborne mist that can cause occupational asthma and 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.

  • Make sure the booth/room runs at slight negative pressure so that if there are any leaks, air is drawn into the booth/room rather than paint mist leaking out into the workshop.

  • 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.

What Can RCS Do For You?


RCS's fully qualified and experienced engineers can design, install, test and maintain your LEV extraction systems.


RCS's engineers will endeavour to provide you with the most effective and cost-efficient solution for paint fume, fully COSSH compliant, following current HSE guidelines and your own individual requirements. Call us on +44(0)1563 546807 or click here to contact us for more information.