PRESIDENT’S COLUMN
ASTHMA, ISOCYANATES AND THE GROUP AUTHORITY LICENCE This is essential reading for those using MDSH25/4 On 4th November 2020 the HSE published statistics (https://www.hse.gov.uk/ statistics/causdis/asthma.pdf) on workrelated asthma in Great Britain for 2019. The data suggest that the rate of increase of new cases per year continues to rise, continuing a 4-year trend. Each year there are an estimated 17,000 new cases of self-reported “breathing or lung problems” caused, or made worse, by work. The most common cited causes of occupational asthma by chest physicians continue to be isocyanates and flour/grain. This article focusses on the former. The legal framework for protecting workers’ health is enshrined in The Control of Substances Hazardous to Health (COSHH) Regulations. Employers are required to assess the risks to health from isocyanates, and put in place appropriate control measures. As the target organs are the lungs the most significant route of exposure is by inhalation. A fundamental part of the legallyrequired risk assessment is the measurement of exposures by inhalation. This requires the generation of valid data from workers’ breathing zones, and the comparison of these exposure measurements to Workplace Exposure Limits (WELs). Those of you reading this who are occupational hygienists will recognise the above approach as the standard way of working.
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As with any other substance, you would turn to the Method of Determination of Hazardous Substance (MDHS) series of HSE Guidance Notes for information on approved, validated methods for carrying out such exposure measurements. This would identify MDSH25/4 as the method of choice. Therein lies the problem, because MDHS25/4 is unique! MSHS25/4 is the only sampling method in the series that requires the use of a substance classified as a drug under Schedule 1 of the Misuse of Drugs Regulations 2001. This substance, 1-(2-methoxyphenyl) piperazine (‘1-2MP’), can only be legally used by persons working under a Home Office licence – and only then if the work is carried out in strict accordance with the conditions laid down in the licence. Alternative sampling methods are available for isocyanates, however, they have drawbacks. They typically fail to measure the total reactive isocyanate group (TRIG) concentration necessary for direct comparison against the WELs. Hence MDHS25/4 remains the most appropriate method for measuring worker exposures and the method recommended by the HSE. The health of workers would clearly be compromised if MDHS25/4 could not be used for the purposes of risk assessments. For this reason,
the Home Office has granted a Group Authority Licence (GAL) allowing BOHS Members who belong to the Faculty of Occupational Hygiene permission to use sampling media containing 1,2-MP for the purposes of isocyanate monitoring to MDHS25/4. This is a key benefit of BOHS Membership as non-licenced hygienists cannot offer this service. The Home Office carries out audits on BOHS to ensure the Licence conditions are being met. The conditions are stringent and require 1,2-MP to be stored, used, and transported with similar management controls to other controlled drugs. BOHS is required to report annually to the Home Office on the safeguards put in place to ensure the conditions are met, together with information on quantities used. All incidents and issues are reported to the Home Office, who have the option of carrying out their own investigations. All of the GAL conditions are embodied in the BOHS Standard Operating Procedure (SOP) which is accessible from the BOHS website. The SOP does not give details of how to carry out sampling. This is provided by MDHS25/4. However, following the SOP ensures compliance with the GAL. All Members must strictly comply with the SOP to avoid the potential revocation of this licence.
A fundamental part of the legally-required risk assessment is the measurement of exposures byinhalation. This requires the generation of valid data from workers’ breathing zones,
BOHS.ORG
