Getting on top of Long Latency Disease

On Wednesday 9 March I attended a meeting on “long latency disease” organised by the BOHS North West Region. I guess the subject wouldn’t mean much to many people. In fact it simply means diseases that take a long time to develop following exposure to hazardous substances. This includes diseases such as cancer caused by asbestos and other chemical agents and respiratory diseases such as silicosis, chronic obstructive pulmonary disease (COPD) and asthma.

The meeting was chaired by Alex Bianchi (ExxonMobil), BOHS President Elect. Alex also spoke about a number of issues relevant to BOHS Members, including the BOHS strategic review, the new Occupational Safety and Health Consultants Register, BOHS’s International Partners scheme and the new Associate Grade Membership of the Faculty of Occupational Hygiene.

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Rachel Beattie

The first speaker was Rachel Beattie of the Health and Safety Executive (HSE) who spoke about  their approach to addressing Long Latency Disease., using their campaign on asbestos as an example. Currently there are 4000 people die every year in Great Britain due to past exposure to asbestos. About 1,000 of those are tradesmen such as electricians and plumbers and HSE’s research suggested that many of them still didn’t see asbestos exposure of something of concern and even where they were aware of the risks, they didn’t know how to protect themselves. The campaign focused on delivering simple, hard hitting messages via media relevant to the target groups.

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Rachel emphasised the need to embed changes in attitude and behaviour, recognising that this was a lengthy process. There are no “quick fixes”.

There was some debate about whether the messages were still relevant given that the exposure of tradesmen to asbestos working on buildings were considerably different to those experienced 30 or 40 years ago. Today they should not be working directly with asbestos  as they would have in the past. The main way they would be exposed today would be by accidentally disturbing asbestos containing materials in the building fabric and the best way to address these risks is to ensure that the materials are properly managed by the owners of the buildings. The question was raised as to whether the HSE’s campaign was misdirected and that it was more relevant to ensure that building owners fulfilled their obligations. An interesting and valid point, but, with limited time available, it wasn’t possible to explore it properly.

Chris Keen  of the Health and Safety Laboratory (HSL) – spoke about his work on a joint HSE/HSL project to developing the evidence base for exposures to carcinogens in the workplace.  32 substances that are known or suspected carcinogens (not including asbestos) were investigated using biological monitoring as the main exposure tool, supplemented by air sampling.

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Extensive surveys, in many cases involving large numbers of samples, were carried out in a number of target industries, in most cases working in partnership with industry groups.  Concentrating on a number of specific industries, including plastics, the use of MbOCA in polyurethane production, the chemical supply industry, surface finishing (better known as electroplating) and foundries, Chris provided outlines the types of exposures they’d found and was able to provide some examples of where companies had been able to reduce exposures as a result of the intervention.

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Although the project is mainly intended to increase the information available to the HSE, the findings from many of the surveys are being published so that they will be available in the public domain.

It was interesting to hear how biological monitoring had been the main technique used to evaluate exposures rather than air sampling. Measuring the concentration of the contaminants or their metabolites in blood, breath or urine is probably the most accurate way of assessing exposure as it evaluates what is actually absorbed by an individual and considers all routes of exposure. Air sampling can only measure the concentration in the breathing zone; it can’t accurately assess what is taken into the body which depends on factors other than the concentration in the air. It also can’t take into account exposure that may occur via skin absorption and ingestion. Yet air sampling is the main approach normally used in occupational hygiene surveys. So Chris’ presentation certainly raised some food for thought. However, as Chris pointed out, air sampling can still provide useful supplementary information – helping to identify routes of exposure and with the specification of controls.

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In her talk on “Controlling Exposures to Silica at Stonemasonry“ Marjory Mitchell an Occupational Hygiene Specialist Inspector with HSE, showed how a small stonemasonry company had modified and improved their local exhaust ventilation system to improve control over the dust generated during the cutting of blocks of stone.  High exposures to respirable crystalline silica, which can cause silicosis, a serious lung disease, and which is also associated with lung cancer, can occur during stonemasonry processes. A good standard of control is needed to minimise the risks to health.

The original system had a flexible arm hood, which, as is often the case when these systems are used on dust generating processes, was largely ineffective at controlling the contaminants. A new hood, a partial enclosure with receptor characteristics, was constructed and installed and, while not perfect, substantially increased the degree of control. The case study provided a good illustration of how by applying the principles set out in HSE guidance, exposure to hazardous substances can be reduced.

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Initial design

 

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Improved LEV hood

The final speaker was John Parker, Chief Executive of the Cast Metals Federation, who spoke on  “Partnership Working Bringing about Change in the Foundry Industry”.

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John Parker

The foundry industry had participated in the HSL/HSL project that Chris Keene had described in his earlier presentation. John talked about the types of chemical hazards created by foundry and gave an overview of the objectives and deliverables of the foundry industry’s collaboration with HSE. He ended his talk by saying that “the cast Metal Federation, through its partnership with HSE, is committed to bring about change in the UK foundry industry” .

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