Why test for isocyanate exposure?
Isocyanates are one of the leading causes of occupational asthma
in the UK. As respiratory sensitisers, exposures to isocyanates
should be kept as low as reasonably practicable and this often
requires the use of respiratory protective equipment (RPE).
Biological monitoring is a simple and cost-effective way of
checking that control measures are working and being used
correctly. Our case studies show the utility of using
biological monitoring for assessing isocyantate exposures in
floor screeding applications.
Isocyanates are widely used in industry but have particular
application in spray painting, foam and polyurethane manufacture
and in adhesives. HSE
recommends that vehicle spray painters undertake biological
monitoring annually to check that exposure is being adequately
controlled. Biological monitoring can be carried out by anyone who
understands the principles (see HSE's
guidance) but you may find it convenient to arrange annual
isocyanate testing as part of your health surveillance (health
surveillance is required for workers using isocyanates).
How to sample?
HSE Science and Research Centre offers
UKAS-accredited biological monitoring analysis for HDI and IPDI
(found in spray paints), TDI (foams and glues) and MDI (resins and
hardeners). A urine sample is required and should be taken at the
end (within an hour) of a period of potential exposure. Sampling
should reflect normal working practice. Urine samples should be
collected in bottles containing a citric acid preservative. We
provide bottles and packaging as part of the analysis cost.
What to test for?
In order to improve the quality of our data collection, we would
like to encourage clients to only request the analysis of the
isocyanates actually used by the workers being tested - most only
use one or two isocyanates. A new request form has been developed for
isocyanates to help you identify which isocyanates are in
use. We are also willing to look at your safety data sheets
if you are unsure which isocyanates you should be monitoring.
What do the results mean?
We have produced guidance on biological monitoring for
isocyanates for both employers and employees. HSE
scientists will help interpret results from samples that we
have analysed where required. There is also a UK guidance
value (BMGV) to
Your report will contain one of two notes:
- Evidence of exposure to requested isocyanates. Check control
measures and training. Refer to HSE guidance regarding
- No evidence of exposure to requested isocyanates. Re-test
in one year.
Where results exceed the current guidance value (1 µmol/mol
creatinine) we would recommend that re-testing is done shortly
after checking the control measures and ways of working.
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