Health in Construction

A couple of weeks ago I travelled down to Birmngham to give a talk on behalf of the BOHS Breathe Freely initiative at the Health and Wellbeing event at the NEC. The Title of the talk was Managing Health in Construction – What Good Looks Like. An annotated version of the slides I used during the talk are now available on Slideshare

To prepare for the talk I did a little research on the meaures that are readily available to control exposure to contaminants, particularly dust, during common activities on construction sites. A number of studies have been done, both on-site and in the laboratory to assess the effectiveness of water supression and on-tool extraction for power tools. These studies have confirmed just how they can be.

For example

  • A large scale study in Ireland by Healy et al showed that the use of local extraction built into on-tool shrouds could reduce dust exposures by up to 99%
  • Laboratory tests by Thorpe et al showed water suppression on cut-off saws reduced dust levels by up to 99%

Despite this, in a large proportion of cases these engineering controls are not being used with reliance placed on respiratory protection which is often incorrectly used and inadequately managed. So one of the main aims of the BOHS Breathe Freely initiative is to raise awareness of the types of controls that can be used to reduce exposure. Hopefully in the not too distant future we’ll see water supression and on-tool extraction become the norm rather than the exception.



Measurements of the E€ectiveness of Dust Control on Cut-off€ Saws Used in the Construction Industry. Thorpe et al. Ann Occup Hyg Vol. 43, No. 7, pp. 443-456, 1999

An Evaluation of On-Tool Shrouds for Controlling Respirable Crystalline Silica in Restoration Stone Work.  Healy et al. Ann Occup Hyg 2014;58:1155-1167


Breathe Freely

On the evening of 28 April, Workers’ Memorial Day, the Breathe Freely initiative, which aims to raise awareness of respiratory disease in the construction industry, was launched at a reception at the Merchant Taylor’s Hall in London. The room was packed with 140 people, mainly representatives from the Construction industry.


Breathe Freely is a collaborative initiative led by BOHS in partnership with key organisations within the construction industry. It will provide guidance, tools and resources that facilitate the recognition, evaluation and control of workplace exposures leading to the implementation of a recognised management standard. The aim is not just to raise awareness of the problem but also to effect action by providing practical solutions through sharing of best practice and encouraging implementation of effective exposure control.

Exposure to hazardous substances that can cause respiratory disease is a serious, but often unappreciated, risk for construction workers. However, the number of workers affected can be reduced dramatically if employers adopt good practice and introduce appropriate, cost effective, control measures.  The BOHS led Breathe Freely campaign will be a major step forward in highlighting both the risks and, very importantly, the measures that can be used to minimise them. Diamond Environmental is proud to be a supporter of the initiative

Health and Safety in Engineering

On Tuesday this week I went down to London to represent BOHS at a reception in the House of Commons held to launch a new document on the business case for health and safety in engineering. It was produced by the Inter-Institutional Group on Health and Safety, an organisation made up of representatives from the engineering professional bodies.

The document highlights the essential and growing role of engineering in supporting health and safety risk management and economic sustainability, listing some key steps for engineers, managers and government to consider. The business case for health and safety engineering solutions is outlined, providing real-life examples of many engineering-related successes and failures, supported by an explanation of how and why the case needs to be made more strongly. The examples are largely safety related, particularly focussing on major construction projects, but there is mention of occupational health.

The need for health and safety to be considered early in an engineering project is stressed and that really is key. It’s usually much easier to incorporate effective controls at the design stage. Retrofitting engineering controls such as containment and local extraction is not always easy and often results in ineffective design and use of “off the shelf” solutions which may not be appropriate to the nature of the risk.

A multidisciplinary approach is recommended with project engineers involving health and safety specialists, including occupational hygienists, at the design stage and throughtout the project. Working togethor problems can be identified and resolved at an early stage.

It’s good to see engineers taking health and safety seriously. Hopefully the document will be widely circulated and the principles it advocates implemented, reducing accidents and injuries and preventing ill health.

Low Toxicity Dusts–Part 2


In my last post I discussed the evidence that suggests that the “trigger values” of 10 and 4 mg/m3 that are widely used as such by many occupational hygienists for “low toxicity dusts” where an official Workplace Exposure Limit (WEL) hasn’t been set, are probably too high to prevent ill health in workers. Despite considering the evidence, the HSE’s Advisory Committee on Toxic Substances (ACTS), has decided NOT to take any action other than to recommend an awareness raising campaign for those exposed to dusts to highlight possible risks to health. However, a number of independent experts and the Trade Unions were not happy with this decision. And following the workshop at the recent BOHS Conference in Cardiff, I’m sure that many practising occupational hygienists feel that applying limits of 10 mg/m3 for inhalable dust and 4 mg/m3  for respirable dust is no longer appropriate.

In my experience there are very few workplaces where inhalable dust exposures exceed 10 mg/m3. For most common processes, it is usually “reasonably practicable” to reduce exposure well below this level by applying common engineering controls such as containment, partial containment and well designed local exhaust ventilation. And in some cases simpler measures such as improving housekeeping or the way the job is carried out, may be enough. So I don’t think that it would be too expensive for industry to work to a lower limit. The TUC has recommended values of 2.5 mg/m3 for the inhalable fraction and 1 mg/m3 for the respirable fraction of “low toxicity” dusts as interim limits. I think these are achievable in practice for most companies if they apply industry best practice. This seems a common sense approach which would reduce the risk to health for workers exposed to these dusts.

However, there there is a problem – there are a number  of “poorly soluble dusts of limited cytotoxicity”, to use the HSE’s preferred term, for which WELs have been established using the 10 and 4 mg/m3 values . For example, aluminium oxide, barium sulphate, cellulose, graphite, gypsum starch and titanium dioxide. There’s about 20 in all. If the HSE doesn’t reduce the limits for these substances, and there is no indication that they intend to do that, it may be difficult to convince employers that they need to work to a lower level than the legal limit.

I guess the best approach would be to argue that COSHH requires that even where a limit is set, the “principles of good control practice” set out in in schedule 2a, have to be applied. In my experience, in nearly all cases where we’ve carried out dust surveys there are usually simple measures that can be taken to reduce dust levels, even when exposures are below a WEL.  So, in most cases by implementing common sense measures and established industry good practice it should be possible to reduce exposure down to the TUCs recommended levels, even for those dusts where a WEL with a higher value exists.

Design and management of controls

I’ll be making a contribution to the BOHS Conference in Cardiff this year, first thing on the Thursday morning, titled Managing the Design and Implementation of Controls – A Review

The usual definition Occupational hygiene is that it is :

the discipline of anticipating, recognising, evaluating and controlling health hazards in the working environment with the objective of protecting worker health and well-being and safeguarding the community at large.’ (Source : International Occupational Hygiene Association)

Recognition and evaluation are important steps but, for me, they’re a means to an end, not an end in themselves. As occupational hygienists our priority has to be control. The other steps should really be about providing us with information to help us to make decisions on minimising risks to health.


Unfortunately, controls are often badly designed and implemented, meaning that they are of limited effectiveness. There are a number of reasons for this, but, in my experience, ineffective control of exposure often occurs due to failures in the management process. If employers are to improve on this they need guidance. And occupational hygienists and other H & S professionals need to be able to analyse problems to help management avoid and overcome them.


My talk will outline a management framework that sets out the key steps for the effective specification, design and implementation of control measures. I’ll be including a number of case studies showing how the framework can be used to analyse and identify problems.

Inevitably, I only have limited time and can only provide a brief introduction to the framework, so I’ve produced a Slideshare presentation that provides some additional background and more details.

Risk Management Measures in the real world


At the end of October, I travelled over to Helsinki for a few days. I’d been invited to deliver a short course on “Risk management measures in a REACH context”  to personnel working for the European Chemicals Agency* (ECHA) who are responsible for evaluating the dossiers chemical manufacturers have to submit under the European REACH Regulation. Over 30 people attended the course, a much bigger number than I’d normally prefer. However, they were a really nice group of people who were keen to listen and contribute to the discussion making it an enjoyable experience for me, and, I hope, for the attendees. It was good to have the opportunity to put forward my perspective on how effective risks from hazardous substances are controlled in practice in the “real world of industry.

The principle objective of REACH is to protect human health and environment from chemical hazards, ensuring that risks from the use of chemicals are properly controlled. To achieve this, manufacturers have to undertake risk assessments for all “exposure scenarios” where their products are used and produce “extended safety data sheets” for substances, which must include appropriate “risk management measures”. We’re now starting to see these new style data sheets coming through to users.

During the training session, we looked at how exposures to chemicals vary and the practicalities of obtaining adequate data for the risk assessment process. However, the main discussion centred on the realities of how “risk management measures” are implemented in industry, based on my experiences helping companies to control the risks from using hazardous substances.

I think that there is a widespread impression that controls are much more effective than they are in practice. There are lots of reasons for this, which I’ve discussed in some previous posts. Problems can occur during all the key steps involved in the design and implementation of controls – see my Slideshare presentation and this post for some examples.

It’s a particular problem with local exhaust ventilation systems. In my experience they are rarely well designed and, in practice,  their influence on exposure is considerably less than the users (and designers/suppliers) believe. The “lower tier” exposure models commonly used to prepare the REACH risk assessments can assume that LEV is up to 90% effective. The system would have to be well designed and properly used and maintained for this to be the case and I think that it is rare for it to be achieved in practice. Consequently, exposure modelling with lower tier models can considerably overestimate the reduction in exposure achieved by LEV.

Manufacturers and importers of chemicals need to make judgements about the effectiveness of controls when carrying out their risk assessments and also when deciding on what risk management measures are needed. The danger of overestimating how good they are could compromise their risk assessments and result in risk management measures being specified that won’t adequately control exposure. It’s important, then, to have a realistic appreciation of the “real world” effectiveness of common controls.

Those extended data sheets I’ve seen so far seem to specify realistic controls for the exposure scenarios. However, they are phrased in very general terms. Again this is likely to be a particular problem with LEV. For many industrial organisers “LEV” means a captor hood – often the flexible “swinging arm” type. As I’ve discussed in a previous post, these are largely ineffective at controlling contaminants. But in many cases if a company follows a general recommendation to install LEV, this is what they’ll buy.  I think that if REACH is really to achieve it’s objective of improving control, then we need to ensure that the advice on risk management measures is as specific as practicable. So with LEV enough details needs to be provided to make sure that the design of the extraction hood is appropriate.

Milling polyurethane blocks at semi automated machine
Inappropriate application of a captor hood

Another problem I’ve noticed with the new style safety data sheets I’ve seen is that where personal protective equipment is recommended the advise is too general. For example, recommending “wear suitable gloves”. This really isn’t any improvement on the older style sheets. Downstream users need more specific advice on what type of gloves are needed, particularly what they should be made of. The reality is that most users don’t have the expertise to select “suitable gloves” and in most cases the gloves used are made of an inappropriate material and are not used and managed properly.  This point is also relevant to other types of personal protective equipment. Again, I’d like to see more specific details provided.


For me a good model for user friendly control advice is the COSHH Essentials control sheets. These provide good, concise advice on control for common processes on a maximum of 2 sides of A4. Where LEV is recommended specific details on the hood design, including an outline diagram, is provided. These sheets aren’t perfect – their advice on personal protection is too vague, for example – but I think that overall they strike the right balance between brevity and the usefulness of the information.

A lot of work has to go into carrying out the risk assessments. It’s important that the output – i.e. the information on risk management measures – should be detailed enough to ensure that controls are properly designed and implemented. Unless this happens there’s a real danger that all the effort will be in vain and an opportunity to substantially improve control of hazardous substances at work will have been missed.

*ECHA’s role is to manage and coordinate the registration, evaluation, authorisation and restriction processes and to ensure consistency in the management of chemicals across the European Union.

Common problems with COSHH assessments

The Control of Substances Hazardous to Health Regulations (COSHH) are undoubtedly the most important legal requirements for occupational hygienists working in Great Britain. They’ve been around for a long time now – the first version being enacted in 1988 – yet, in my experience, there are still many organisations that haven’t completely got to grips with them. One of the main problems is that many employers do not fully understand the Regulations and what they require and often misinterpret them.

In essence, COSHH is relatively straightforward. It simply sets out a framework for the management of risks created by using hazardous substances at work. I’ve often used the following diagram to summarise the main requirements of the Regulations


Employers whose operations involve the use of hazardous substances have to undertake a risk assessment in order to decide on what controls are appropriate. The other measures are then about they need to do to ensure that the controls remain effective (they’re the management controls that I’ve discussed in a previous post).

1. COSHH is about CONTROL

The first mistake employers often make is to forget the real objective of COSHH – i.e. controlling  the risks. They put a lot of work into the assessment, often generating a lot of paperwork, but don’t follow through to implement effective control regimes. The assessment is important – it is needed to establish priorities by deciding on which are the most significant risks, but it is primarily meant to be a tool to allow the employer to develop an action plan. It’s a means to an end not an end in itself.

2. Assess the RISK not the HAZARD

The second common problem is that many employers do not understand how to undertake the assessment.  It is quite common to focus on the substances used taking information from the safety data sheets provided by the suppliers and transferring it to a standard form , in effect, producing a summarised data sheet. This often involves a lot of time and resources, and although such summarised data sheets can be a useful information tool  they are not a risk assessment.

To see why this is the wrong approach it’s useful to take a look at the wording of COSHH regulation 6 which sets out the requirements for the assessment.

‘An employer shall not carry out work which is liable to expose any employees to any substance hazardous to health unless he has

a}made a suitable and sufficient assessment of the risks created by that work to the health of those employees and of the steps that need to be taken to meet the requirements of these Regulations

b) `implemented the steps referred to in sub-paragraph a.”

The key words that I’ve highlighted are “the risks created by the work”. The substances present hazards but, as the Regulations clearly state,  the risks are associated with the use of the substances.

I’ve heard many people state that they have carried out the assessments for all their substances. This normally indicates that they haven’t got it right. It’s not the substances that need to be assessed, but the work involving their use. For example, take a simple case where solvent is used for cleaning purposes. The risks, and the necessary controls,  associated with using a few millilitres applied with a cotton bud are clearly quite different than using several litres of hot solvent in a vapour degreasing bath. It is inappropriate to carry out a risk assessment of the substance – two assessments of two quite different processes are needed.

So the assessment should focus on the process. It should also concentrate on the risk not just the hazard. Risk is often defined as “the probability of harm occurring in practice”. For occupational hygienists it is best summed up by the following equation:


So the hazardous properties are important, but they are only half the story. The key to effective risk assessment, which s often neglected, is understanding the exposure of employees (and anyone else who could be affected by the work).

3. Identify ALL hazardous substances

Most COSHH assessments I’ve seen concentrate only on the substances that are bought in by the company. Yet there can be other substances present which need to be considered such as fumes, dusts and other airborne contaminants generated by the process or reaction products and intermediates in chemical manufacturing. In many cases it is these process generated substances that present the most significant risks, but they are often neglected.

Silica containing dust generated during cutting of paving slabs

4. Consider ALL routes of exposure

Many people carrying out assessments only focus on substances that can be inhaled. But there are other routes by which substances can come into contact with the body and be absorbed. All of these need to be considered.

Skin exposure by immersion (picture source:

Skin exposure is a common problem in industry leading to direct effects on the skin such as irritation, chemical burns and dermatitis and some substances can be absorbed through intact skin (this is something I’ve addressed in a previous post). Ingestion of hazardous substances can sometimes occur – normally due to contamination of foodstuffs, often following skin exposure. Penetration through the skin can occur by injection where workers are handling needles (e.g. healthcare workers) or where the skin has been abraded or otherwise damaged.

5. Identify controls and other management measures

The other common mistake is that employers often do not properly consider the measures needed to control the risks. They forget that controlling risk is the objective of COSHH and that the Regulations specifically require that the assessment must set out “the steps that need to be taken to meet the requirements of …. (the)…Regulations””.  This means that they need to decide on what controls are needed and what other measures might be needed (i.e. on the use, maintenance and testing of controls, air monitoring, health surveillance and information, instruction and training)

The first step in solving a problem is to recognise that it exists, but we then need to decide how to resolve it. I’ve set out some of the common problems with COSHH that I come across; I’ll consider how to avoid them when carrying out a COSHH assessment in my next post.