Important information regarding use of isocyanates
Isocyanates: Are your control measures preventing exposure?
Isocyanates are highly reactive chemicals used in making a variety of products, including paints, foams and glues. Exposure to isocyanates can cause occupational asthma - one of today's most common work-related lung diseases. Occupational asthma can cause serious ill health and result in major changes to the lifestyle of affected people. In some cases, the sufferer has to change jobs to stop their asthma symptoms from getting worse. However, if adequate control measures are in place the condition is preventable.
Isocyanates are often used in industry, for example:
- two-pack spray paints (e.g. hexamethylene diisocyanate, HDI);
- some glues and hard wearing plastics (e.g. toluene diisocyanate, TDI);
- making, cutting, grinding or heating polyurethane foams (e.g. methylene diphenylene diisocyanate, MDI);
- production of polyurethane paints, varnishes and elastomers (e.g. isophorone diisocyanate, IPDI).
To control the risk of asthma, isocyanate exposure needs to be kept at very low levels. Even brief exposures to isocyanates can cause sensitisation. Once a person has been sensitised, exposure to low levels can still cause an asthma attack. The law requires employers to control exposure to isocyanates to a level, which is as low as is reasonably practicable. But as an employer, how can you tell whether you are doing enough to control the exposure of your employees to isocyanates?
According to the Health and Safety Executive, the only practical way of measuring an employees’s exposure to isocyanate is by analysis of isocyanate metabolites in a urine sample. This is a validated technique to determine whether an employee wearing air fed breathing apparatus is being adequately protected and a benchmark against which to compare exposure measurement results.
Given the risks to employees’ health and the reliance upon breathing apparatus to control exposure, an adequate risk assessment would indicate that exposure needs to be monitored to maintain adequate control. As biological monitoring is the only practical measure of exposure, it becomes requisite for ensuring the maintenance of adequate control of the exposure of employees to isocyanates (COSHH Reg 10(1)). Biological monitoring should be carried out during the first few months of employment to show that RPE and working practices are sufficient to prevent isocyanate absorption. The frequency of urine samples for employees should typically be once per year (but would be more frequent if half-mask breathing apparatus is used).
Biological monitoring is a new requirement and initial enforcement is likely to be advice/ letter. As the practice becomes established, HSE Enforcement Management Model indicates that an Improvement Notice requiring biological monitoring would be appropriate unless the employer can demonstrate by some other method that adequate control is being achieved. Note that biological monitoring for isocyanates DOES NOT provide information about a person’s heath; it indicates whether exposure to isocyanates is occurring.
What is Biological Monitoring?
Biological monitoring (BM) is used to assess exposure by the measurement of a chemical or its breakdown products in blood, urine or breath. For isocyanates, a urine sample from a person is all that is needed for BM.
Why use Biological Monitoring for isocyanates?
BM is unique because it can measure how much of a chemical has actually entered a person's body, rather than how much is in the environment around them. Control of exposure to isocyanates usually relies on engineering controls such as spray booths and respiratory protective equipment such as airfed breathing apparatus. By using BM you can tell whether control measures like these are working and whether they are used correctly.
Sound Advice Safety & Health Ltd in conjunction with the Health & Safety Laboratory (HSL) can provide a confidential service for the biological monitoring of isocyanates, from the issue of the testing kits and help with the procedure, to advice and assistance with the results.
If you would like more information regarding iscocyanate monitoring or there is anything else we can help you with please fill in the contact us page with details of your enquiry.
