Biological Monitoring – Isocyanates

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Guide for employers

Guide for employees

Isocyanates are found in 2 pack (2K) spray paints, adhesives and floor screeding products and are a leading cause of work-related (occupational) asthma.

Employers should ensure that exposure to isocyanates is kept as low as reasonably practicable (ALARP) by reducing the potential for skin contact and the inhalation of spray and vapour. This is generally done using a range of control measures including the provision of gloves and coveralls, use of ventilated spray booths, air fed breathing apparatus and installation of extracted gun cleaners etc.

If using isocyanates you should undertake biological monitoring (urine testing) as part of your annual health surveillance programme to monitor employee exposure. It is important to note that the urine test results are a measure of the individuals isocyanate exposure and should guide an employer to take necessary action to ensure that control measures are effective, they are not an indication of an individual’s current health status.

Employers should ensure employees in the vicinity of isocyanate use are also considered when undertaking your workplace risk assessment and method statement (RAMS) relating to the handling and use of isocyanates.

Sample Provision - Isocyanates

Annual urine collection and testing for the breakdown products (metabolites) associated with isocyanates is advised to supplement any air sampling which may also take place within the workplace. Employers MUST obtain informed consent for urine testing from each employee being tested.

Urine sample should be collected at the end of the working week and end of the working day, ideally within an hour of the last potential exposure. The sample is collected in a small (30ml) sample bottle containing a small amount of citric acid preservative.

*It is important that this is not tipped out in error by the employee when providing the sample.

Employees should close the lid firmly and mark it with their name and the date of collection. Samples should be sent to the laboratory within 48 hours and kept chilled or frozen if necessary to ensure that samples can be tested.

*Where IWH are collecting the samples and processing/posting these for you please ensure that the above information is considered when considering the collection time/day.

Testing and Results Analysis

The laboratory will only test the urine for the substance agreed i.e. Toluene diisocyanate (TDI), where you are unsure what your staff may need testing for, please contact IWH for advice.

Urine samples are normally tested annually (or every 6 months) but may need to be done more frequently where samples are above the guidance value.

Where results are below the guidance values this is often an indication of comprehensive risk assessments, good training and instruction, use of respiratory protective equipment (RPE), effective donning and doffing procedures and effective use of mechanical controls.

Where the results are above the guidance value this may indicate that the workplace controls are not working effectively, and an employer should ensure that suitable checks are made to ensure that any necessary improvements are made. Further samples should be collected at intervals to confirm that the any improvements or changes to the process have been effective.

Even with good workplace controls employers may note that up to 10% (1:10) samples will be above the guidance value.

Brief Guide for Employers

• Explain to employees that you are undertaking urine testing to monitor exposure to isocyanates that could cause occupational asthma. Advise that this will normally be done once a year, unless the results show there is a potential problem.

• Advise them to provide a urine sample at the end of a typical spray session (working day) where they have been using isocyanate products.

• Advise them that only substances related to isocyanates (‘biomarkers’) will be measured in the sample – no other testing will be undertaken i.e. For drugs, alcohol etc.

  *They have not consented for it and you are not paying for it.

• Advise them that the results will not say anything about their health or risk of ill-health, only their exposure to potential substances.

• Ask them if they will let you see the laboratory results.

• Advise them that the abnormal results may indicate that existing controls are not working properly, and that further urine samples may need to be collected if this occurs.

Insight will provide a small (30ml) sample bottles containing a little white preservative and appropriate packaging.

• Your employee should direct a sample of urine into the bottle at the end of the working day and close the bottle firmly.

• Make sure employee knows to put their name and the date on the sample label before placing the bottle in the packaging provided.

• Send the samples directly to us so that we can process for the laboratory or we will collect depending on agreement.

  
  

Brief Guide for Employees

Insight Workplace Health will provide small (30ml) sample bottle containing a little white preservative, make sure this is not tipped out accidentally as otherwise a further sample may need to be collected.

You should collect a sample of urine (about half – two thirds full) in the sample bottle at the end of the working day as advised by your employer and close the lid firmly. Nobody wants leaks!

Maintaining the Sample Integrity

Samples for TDI must be received in appropriate bottles containing preservative and should be received within three days of posting.

Where samples have been despatched the same day or day after collection and have been received by the laboratory within three days of posting, there should be no integrity issues.

Where samples have been refrigerated or frozen as appropriate prior to shipping and have been received by the laboratory within three days of posting, there should be no integrity issues.

Need Support?

If you have questions about isocyanate biological monitoring, sample collection, or want to implement a compliant health surveillance programme for your business, contact Insight Workplace Health for guidance and support.