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LEV testing - isocyanates
Isocyanates - found in two-pack (2K) paints, lacquers and some coatings, widely used in vehicle body shops - are one of the leading causes of occupational asthma in the UK. They're respiratory sensitisers: once they've sensitised someone, small exposures can trigger severe asthma attacks, and there's no cure. Here is how isocyanates affect the body, and why the exposure has to be controlled tightly. This is general information, not clinical advice.
The short answer
Isocyanates are the reason two-pack (2K) vehicle paints harden to a tough finish - and the reason spray-painting is one of the highest-risk trades for occupational asthma. They're used widely in vehicle body shops and other spraying, and they affect the body in a specific, serious way. Here's how, and why the exposure has to be controlled tightly. This is general information, not clinical advice. Respiratory sensitisers. Isocyanates are respiratory sensitisers - substances that can make the airways hypersensitive - and they're one of the leading causes of occupational asthma in the UK. Spray-painters are at particularly high risk: automotive spray-painters are far more likely to develop occupational asthma than workers in most other jobs. So isocyanates aren't a minor irritant - they're a major cause of a serious, often career-ending respiratory disease. How sensitisation works. The way isocyanates harm is through sensitisation. When isocyanates are breathed in, they can react with proteins in the lining of the airways. In a susceptible person, this leads the immune system to become hypersensitive to isocyanates - it develops an exaggerated immune response to them. Once that's happened, the person is sensitised. And once sensitised, the person's airways react to isocyanates: exposure triggers an asthmatic response - wheezing, chest tightness, breathlessness, coughing - which can be severe. So the harm isn't simple irritation; it's the immune system being primed to over-react to isocyanates thereafter. The grim features: no cure, and a tiny trigger. Two features make isocyanate sensitisation especially serious. There's no cure: sensitisation is usually permanent, so a sensitised person reacts to isocyanates for life. This typically means they can't keep working with isocyanates (continued exposure triggers their asthma), so it often ends their career in that trade - a life-changing outcome. And once sensitised, the trigger level is tiny: the person reacts to exposures far below the level that caused the sensitisation in the first place. So even small, brief exposures - which wouldn't sensitise a new person quickly - can trigger a severe attack in a sensitised person. This means a sensitised worker can't safely be around isocyanates at all. Immediate or delayed reactions. The asthmatic reactions can be immediate (coming on soon after exposure) or delayed - sometimes appearing several hours later, in the evening or at night, away from work. This delay can obscure the link to work (the person feels ill at home, not at the spray booth), which can delay recognition that the asthma is occupational. So symptoms that appear away from work, hours after exposure, can still be caused by isocyanates at work. Other effects. Besides the respiratory sensitisation, isocyanates can irritate the skin, eyes and airways on contact or exposure. And skin exposure may also play a part in sensitisation. So while the respiratory sensitisation (asthma) is the headline hazard, isocyanates are irritant too, and skin contact matters. Why spraying is high-risk, and how it's controlled. The exposure is a particular problem in spraying, because spraying produces a fine aerosol mist of the paint that's very easily breathed in - so spraying isocyanate paint can give high exposure unless tightly controlled. This is why spray-painters are at such high risk. So control has to be tight: spraying done in a properly designed and ventilated spray booth with effective extraction (LEV) that removes the mist; suitable respiratory protection (for spraying isocyanates, this typically means air-fed breathing apparatus, because the exposure is so high and the consequences so serious); good practices (allowing the booth to clear before entering unprotected, skin protection); the LEV maintained and thoroughly examined and tested regularly to confirm it works; and health surveillance to catch early signs of sensitisation before it becomes established asthma. Given that there's no cure, preventing sensitisation through tight control is everything. So the exposure is controlled tightly through booth, extraction, air-fed RPE, good practice, testing and health surveillance (covered in the vehicle-body-shops-lev-testing-for-spray-painting page). The takeaway. So isocyanates in paint affect the body as respiratory sensitisers: breathed in, they can sensitise the airways so the immune system becomes hypersensitive, causing occupational asthma - with no cure, permanent sensitisation, and reactions to tiny exposures thereafter, sometimes delayed. Because spraying gives high exposure to an easily-breathed mist, and because sensitisation is incurable and career-ending, the exposure must be controlled tightly - with spray-booth extraction (LEV, tested), air-fed RPE, good practice and health surveillance. This is general information, not clinical advice - an occupational health professional advises on health effects. This is general information.
Key points
Respiratory sensitisers
Isocyanates are respiratory sensitisers - substances that can make the airways hypersensitive - and they're one of the leading causes of occupational asthma in the UK. They're the hardener component in two-pack (2K) paints, lacquers and some coatings, used widely in vehicle body shops and other spray-painting.
Spray-painters are at particularly high risk: automotive spray-painters are far more likely to develop occupational asthma than workers in most other jobs. So isocyanates aren't a minor irritant to shrug off - they're a major cause of a serious, often career-ending respiratory disease, and the trade that uses them most (vehicle spraying) is one of the highest-risk for occupational asthma. This is what makes isocyanate exposure a priority to control. How exactly they cause this - through sensitisation - is covered next, and it's the key to understanding why the control has to be so tight. So respiratory sensitisers - a leading cause of occupational asthma - is the headline: isocyanates sensitise the airways and cause occupational asthma, hitting spray-painters especially hard. So they're a top cause of work-related asthma. This is general information, not clinical advice. This is general information.
How sensitisation works
The way isocyanates harm is through sensitisation. When isocyanates are breathed in, they can react with proteins in the lining of the airways. In a susceptible person, this leads the immune system to become hypersensitive to isocyanates - developing an exaggerated immune response to them. Once that's happened, the person is sensitised: their immune system is now primed to over-react to isocyanates.
And once sensitised, the person's airways react to isocyanates - exposure triggers an asthmatic response: wheezing, chest tightness, breathlessness, coughing - which can be severe. So the harm isn't simple irritation (though isocyanates are irritant too); it's the immune system being turned hypersensitive, so that the person's own immune response to isocyanates causes their asthma. This is why it's called sensitisation - the person is made sensitive to the substance, so they react to it thereafter. The process of becoming sensitised usually takes repeated exposure over time, though it can happen after a shorter period of high exposure. So how sensitisation works - the immune system turned hypersensitive - explains the mechanism: isocyanates prime the immune system to over-react, causing asthma on exposure. Why this is so serious (no cure, tiny trigger) is next. So sensitisation makes the immune system over-react to isocyanates. This is general information, not clinical advice. This is general information.
No cure, and a tiny trigger
Two features make isocyanate sensitisation especially serious. First, there's no cure: sensitisation is usually permanent, so a sensitised person reacts to isocyanates for life. This typically means they can't keep working with isocyanates - continued exposure triggers their asthma - so it often ends their career in that trade, a life-changing outcome from a workplace exposure.
Second, once sensitised, the trigger level is tiny: the person reacts to exposures far below the level that caused the sensitisation in the first place. So even small, brief exposures - ones that wouldn't quickly sensitise a new person - can trigger a severe asthmatic attack in someone already sensitised. This means a sensitised worker can't safely be around isocyanates at all, even at low levels or briefly. Together, these features are grim: an incurable, permanent condition, triggered by the smallest exposure, that usually ends the person's work in the trade. This is why preventing sensitisation in the first place - through tight control of exposure - is everything, because once it's happened it can't be undone and the person's working life in that trade is effectively over. So no cure, and a tiny trigger - permanent, and set off by the smallest exposure - is what makes isocyanate asthma so serious: it can't be cured and needs almost no exposure to trigger once established. The timing of reactions is next. So sensitisation is permanent and easily triggered thereafter. This is general information, not clinical advice. This is general information.
Immediate or delayed
The asthmatic reactions to isocyanates can be immediate - coming on soon after exposure - or delayed, sometimes appearing several hours later, in the evening or at night, away from work. So a spray-painter exposed during the day might have an asthmatic reaction that evening at home, rather than at the spray booth.
This delay can obscure the link to work: the person feels ill at home, hours after their shift, so they (and even a doctor) may not immediately connect the asthma to the isocyanate exposure at work - which can delay recognising that the asthma is occupational, and delay removing the person from exposure (which matters, because continued exposure worsens it). So it's important to know that respiratory symptoms appearing away from work, hours after exposure, can still be caused by isocyanates at work - a pattern of symptoms that are worse in the evenings or on work days, or that improve on holidays, can be a clue to occupational asthma. So immediate or delayed - reactions can appear hours later, away from work - is an important practical feature: the delayed pattern can hide the work link, so it needs recognising. This is also why health surveillance (which looks for the pattern) matters. So reactions may show up later, away from the workplace. This is general information, not clinical advice. This is general information.
Why spraying is high-risk, and control
The exposure is a particular problem in spraying, because spraying produces a fine aerosol mist of the paint that's very easily breathed in - so spraying isocyanate paint can give high exposure unless tightly controlled. This is why spray-painters are at such high risk: the spraying method itself creates an easily-inhaled mist of the sensitiser. Isocyanates also irritate the skin, eyes and airways, and skin exposure may play a part in sensitisation too, so skin protection matters alongside the respiratory control.
So control has to be tight - tighter than for many hazards, because the exposure is high and the consequence (incurable asthma) so serious. That means: spraying done in a properly designed and ventilated spray booth with effective extraction (LEV) that removes the mist; suitable respiratory protection - for spraying isocyanates, typically air-fed breathing apparatus (supplying clean air), because the exposure is so high; good practices (letting the booth clear before entering unprotected, protecting the skin); the LEV maintained and thoroughly examined and tested regularly (typically at least every fourteen months) to confirm it's still removing the mist; and health surveillance to catch early signs of sensitisation before it becomes established asthma. Given there's no cure, preventing sensitisation through tight control is everything (covered in the vehicle-body-shops-lev-testing-for-spray-painting page). So why spraying is high-risk, and control - a fine mist, needing tight control - closes the picture: spraying gives high exposure to an easily-breathed sensitiser, so it must be controlled tightly, with tested spray-booth LEV, air-fed RPE and health surveillance. So control isocyanate spraying tightly, and prove it works. This is general information. This is general information.
Questions
As respiratory sensitisers - breathed in, they react with proteins in the airway lining and make the immune system hypersensitive to them, causing occupational asthma; once sensitised, exposure triggers wheezing and breathlessness, and they also irritate the skin, eyes and airways. Isocyanates affect the body chiefly as respiratory sensitisers, causing occupational asthma. When breathed in, they can react with proteins in the lining of the airways, and in a susceptible person this leads the immune system to become hypersensitive to isocyanates - developing an exaggerated immune response. Once that's happened, the person is sensitised, and their airways react to isocyanates: exposure triggers an asthmatic response (wheezing, chest tightness, breathlessness, coughing), which can be severe. So the main harm is the immune system being turned hypersensitive, so the person's own immune response to isocyanates causes their asthma. Isocyanates are one of the leading causes of occupational asthma in the UK, with spray-painters at particularly high risk. Besides the respiratory sensitisation, isocyanates also irritate the skin, eyes and airways on contact or exposure, and skin exposure may play a part in sensitisation too. So they affect the body mainly by sensitising the airways (causing asthma), and also by irritation. So they sensitise the airways and cause occupational asthma. So as sensitisers causing asthma, plus irritation. This is general information, not clinical advice. This is general information.
It means they can make the airways hypersensitive - repeated (or high) exposure primes the immune system to over-react to isocyanates, so once sensitised the person develops asthma triggered by isocyanate exposure; and once sensitised, even tiny exposures set it off, with no cure. Isocyanates being respiratory sensitisers means they can make the airways hypersensitive to them - it's a specific and serious kind of harm. When isocyanates are breathed in (usually repeatedly over time, though sometimes after shorter high exposure), they react with proteins in the airway lining, and in a susceptible person the immune system becomes hypersensitive to isocyanates - primed to over-react to them. Once that's happened, the person is sensitised. From then on, exposure to isocyanates triggers an asthmatic response (wheezing, chest tightness, breathlessness) - the person has developed occupational asthma caused by the isocyanates. The crucial consequences of being a sensitiser are that there's usually no cure (sensitisation is permanent) and that, once sensitised, even very small exposures trigger the reaction (far below the level that caused sensitisation). So a sensitiser is more dangerous than a simple irritant: it doesn't just cause temporary symptoms, it permanently primes the body to react. This is why isocyanate exposure must be tightly controlled to prevent sensitisation. So it means they can permanently make someone hypersensitive, causing asthma. So they can make the airways permanently over-react to them. This is general information, not clinical advice. This is general information.
No - sensitisation is usually permanent, so a sensitised person reacts to isocyanates for life and typically can't keep working with them, often ending their career in the trade; this is why preventing sensitisation through tight exposure control is everything, since it can't be undone once it happens. No - there's no cure for isocyanate-induced occupational asthma. Once a person is sensitised to isocyanates, the sensitisation is usually permanent - they react to isocyanates for life. This typically means they can't keep working with isocyanates, because continued exposure triggers their asthma (and can worsen it), so it often ends their career in that trade - a life-changing outcome from a workplace exposure. On top of being incurable, once sensitised the person reacts to exposures far below the level that caused the sensitisation, so they can't safely be around isocyanates at all, even at low levels. Together, these mean isocyanate asthma is a serious, permanent, often career-ending condition that can't be reversed. This is exactly why preventing sensitisation in the first place - through tight control of the exposure - is everything: once someone is sensitised, there's no undoing it and no safe level of continued exposure for them. So the emphasis has to be entirely on preventing exposure (with spray-booth extraction, air-fed RPE and health surveillance to catch it early), because there's no cure to fall back on. So no - it's permanent, which is why prevention is everything. So no; it can't be cured, so prevent it. This is general information, not clinical advice. This is general information.
Because spraying produces a fine aerosol mist of the isocyanate paint that's very easily breathed in, giving high exposure unless tightly controlled - so spray-painters (like automotive body-shop painters) are far more likely to develop occupational asthma than most other workers, which is why booth extraction and air-fed RPE are essential. Spray-painters are at high risk from isocyanates because spraying produces a fine aerosol mist of the isocyanate paint that's very easily breathed in - giving high exposure unless it's tightly controlled. The spraying method itself atomises the paint into a breathable mist of the sensitiser, so a sprayer working with two-pack (2K) isocyanate paint can inhale a lot of it without effective controls. This is why automotive spray-painters are far more likely to develop occupational asthma than workers in most other jobs - the combination of a potent respiratory sensitiser and a method that creates high airborne exposure. It's a serious risk given that isocyanate asthma is incurable and career-ending. This is why control in spraying has to be so tight: spraying done in a properly ventilated spray booth with effective extraction (LEV) removing the mist; air-fed respiratory protection (supplying clean air, because the exposure is so high); good practices (letting the booth clear, skin protection); the LEV maintained and tested; and health surveillance. So the spraying method's fine mist is what makes spray-painters especially exposed and at risk. So because spraying creates an easily-breathed mist, giving high exposure. So because spraying makes a fine, easily-inhaled mist. This is general information. This is general information.
Because the asthmatic reaction can be delayed - sometimes appearing hours after exposure, in the evening or at night - so a sprayer exposed by day may react at home; this can obscure the work link, so symptoms worse on work days or improving on holidays can be a clue to occupational asthma. Isocyanate asthma symptoms can appear away from work because the asthmatic reaction to isocyanates can be delayed, not just immediate. While some reactions come on soon after exposure, others appear several hours later - in the evening or at night, away from work. So a spray-painter exposed during the day might have an asthmatic reaction that evening at home, rather than at the spray booth. This delayed pattern can obscure the link to work: the person feels ill at home, hours after their shift, so they - and even a doctor - may not immediately connect the asthma to the isocyanate exposure at work. That can delay recognising the asthma as occupational, and delay removing the person from exposure (which matters, because continued exposure worsens it). So it's important to know that respiratory symptoms appearing away from work, hours after exposure, can still be caused by isocyanates at work. A pattern of symptoms worse in the evenings or on work days, or improving on days off and holidays, can be a clue to occupational asthma. This is part of why health surveillance (which looks for such patterns) matters. So symptoms can be delayed, appearing at home, hiding the work link. So because the reaction can be delayed by hours. This is general information, not clinical advice. This is general information.
By spraying in a properly ventilated spray booth with effective extraction (LEV) removing the mist, air-fed respiratory protection for the sprayer (because exposure is high), good practices (letting the booth clear, skin protection), the LEV maintained and tested, and health surveillance to catch early sensitisation - tight control, because there's no cure. Isocyanate exposure in spraying is controlled tightly, because the exposure is high and the consequence (incurable asthma) so serious. The controls: spraying done in a properly designed and ventilated spray booth with effective extraction (LEV) that removes the isocyanate mist from the air; suitable respiratory protection - for spraying isocyanates, typically air-fed breathing apparatus (supplying clean air to the sprayer), because the exposure is so high that ordinary filtering masks may not be enough; good practices (letting the booth clear of mist before entering unprotected, protecting the skin since skin exposure matters too); the LEV maintained and thoroughly examined and tested regularly (typically at least every fourteen months) to confirm it's still removing the mist; and health surveillance to catch early signs of sensitisation before it becomes established asthma. Given there's no cure for isocyanate asthma, preventing sensitisation through this tight control is everything - the whole aim is to stop exposure causing sensitisation in the first place. So control combines booth extraction, air-fed RPE, good practice, testing and health surveillance. So with booth extraction, air-fed RPE, good practice and testing. So tightly - booth LEV, air-fed RPE, and health surveillance. This is general information. This is general information.
Isocyanates in 2-pack paints cause incurable occupational asthma, and spraying gives high exposure to an easily-breathed mist - so the spray-booth extraction has to work; we thoroughly examine and test spray-booth LEV, confirming it still removes the isocyanate mist and protects sprayers, as COSHH requires and the seriousness demands. Ask us to test your LEV. This is general information.
