BOHS Examination changes


This week we were running M103, “Control of hazardous substances” in Chester. As usual, we had a good group who were keen to learn, worked hard, contributed to discussions and seemed to get on well.  As usual it was a tough exam, but this will be the last course we will have run with the current style of examination. A few weeks ago BOHS announced that from November the 1st all module examinations will have a new format.

The exam will still be in two parts but from 1st November

  • Part A will consist of 40 short answer questions rather than 60 multiple choice questions.  There are pros and cons for candidates, but the biggest advantage is that there will no longer be any negative marking.
  • Part B will changed so that candidates will be required to answer 5 “micro-essay” questions from a choice of 8.
  • The pass mark will remain at 50%

Personally I think the change to part A will be beneficial. As there is no negative marking it will be advisable to try to answer all the questions. Currently some candidates hesitate on some questions where they are not 100% confident, even though they may know the answer.  And it will only be necessary to get 20 out of 40 right.  Another benefit is that as each question is worth 4 marks, some answers may gain partial marks. This will be particularly helpful with calculation questions where marks can be gained providing an appropriate method is used even if the final answer is incorrect due to a slip in the calculation (working will need to be shown to ensure this happens). Currently a small slip results in a negative mark for an incorrect answer even where the candidate understands the principles involved.

There are still some aspects of the new system that still need to be clarified by the Faculty, in particular:

  • What exactly the “micro essays” will consist of. We haven’t been provided with any clear guidance on this or example questions yet
  • Which type of examination will be given to candidates re-sitting exams taken before 1st November
  • Whether course providers will be given access to the question papers or feedback on the examinations.

We’ll keep you posted on this as soon as we receive the information from BOHS, so watch this space!

Stack Heights

When designing and testing local exhaust ventilation systems we need to pay particular attention to the design of the extraction hoods – where the contaminant enters the system. If this isn’t right then the system is unlikely to be effective at controlling contaminants. However, this doesn’t mean that we shouldn’t ensure that other aspects of the system are properly designed.

In many cases the system will exhaust outdoors and its then important to ensure that any contaminants remaining in the airstream are dispersed effectively so that they do not re-enter the building. This means that they shouldn’t be located too close to any air intakes, vents or windows. It is also particularly important that the stack is high enough. A good “rule of thumb” to follow is that the stack should be at leas one third the height of the building (i.e. it should release at a height 1.33 times the building height).  Its common sense that outlets should also be located away from any windows, doors and inlets. The stacks on the laboratory building shown in the picture above meet these criteria. There are plenty of others out there that don’t! Here’s a few.

BOHS / NVVA conferece on REACH


Conferences ae always a “mixed bag” and this was the case with  the REACH meeting held in Brussels on 30 September/1 October. Overall, it was worthwhile attending and I certainly learned more about how the requirements of REACH relating to occupational exposures were being implemented in practice.  Some of he contributions were a little too basic, given the nature of the conference and the audience, but the majority were useful.

The key points I took away from the conference were:

  • there remains a clear conflict between the requirements of REACH and occupational health and safety legislation. The objectives are the same (i.e. protecting the health of workers and others) but there are significant differences in their approaches  which could potentially lead to conflicting perceptions of risk and requirements for control.
  • insufficient thought was given to how the REACH requirements on hazard and exposure assessment could be applied in practice before the legislation was introduced. Companies implementing the requirements are having to develop the methodologies as they go along and the timescales are too tight to allow then to be properly validated before deadlines have to be met.
  • REACH DNELs (derived no effect levels) are consistently tighter than Occupational Exposure Limits (OELs) due to the major differences in the ways they are established.  This can lead to confusion and as DNELs are used in the risk assessment process to develop “risk management measures” (RMMs) it is highly likely that the REACH process will result in tighter controls being specified than those based on a risk assessment using established OELs.  Although this problem has been known about for a number of years, it has still not been resolved.
  • The tools needed for exposure assessment, which is required to allow RMMs to be specified, are still not fully developed and validated.
  • the Advanced Reach Tool (ART) looks promising and may have wider occupational hygiene applications, but needs to be validated.
  • there are a number of “first tier” exposure assessment tools (i.e. basic exposure modelling methods). A number were described during the conference. It would have been useful to see them demonstrated, using the different tools for the same substance so that their conclusions could be compared.
  • modelling techniques are always going to have their limitations, and this is particularly true for the basic “first tier” models. They need to be used by people who understand exposure assessment and these limitations. Ideally they shoul only be used as part of the exposure assessment process. There is a real danger that this won’t happen in many cases and that RMMS will end up being specified by inexpeienced people using only the flawed, basic models. From what I saw at the conference the models tend to err “on the side of safety” (just like COSHH Essentials). This may mean that worker health won’t be adversely affected but it could have economic consequences for he employers and possibly damage employment.

The occupational hygiene community has the expertise to develop the methodologies, and also has the knowledge and experience to work out how the REACH process could be improved. Unfortunately, I doubt that we have sufficient “clout” to influence the powers that be on this and we are going to have to live with, and try to manage, the consequences once the Regulations start to impact on “downstream users”.



Tomorrow I’ll be heading off to Brussels for the meeting on REACH (REACH: Registration and Beyond: Exposure Scenarios and safe handling advice) organised jointly by BOHS and their Dutch sister organisation, NVVA.

The conference focuses on some important issues, including exposure assessment. REACH requires manufacturers and importers of substances and mixtures to develop exposure scenarios and appropriate risk management measures. This is a major requirement which, with the current methodologies available for assessing occupational, environmental and consumer exposures, would be impossible to achieve. Consequently a lot of work is going into developing exposure models and guidance for exposure assessment which manufacturers and importers will be able to use when the target dates for the exposure scenarios approaches.

I’m hoping that the conference will help to bring me up to date on what progress has been made. There are so many factors that affect exposures in the workplace, so it will be interesting to see how far these have been incorporated into the models being developed. Its a big ask.

Hello world!

Hello world!

This blog has been set up as a forum for Diamond Environmental Ltd. to communicate with people attending our  courses for occupational hygienists.

To get things started I thought I’d make a few comments about what occupational hygiene is. I’m sure most people think that its something to do with cleaning out the works toilets or possibly cleaning teeth.

What is it about then? Well the definition of hygiene provided by the online dictionary is

  1. The science that deals with the promotion and preservation of health.
  2. Conditions and practices that serve to promote or preserve health

In other words its about preventing ill health, so occupational hygiene is simply about preventing ill health caused by work.

In Great Britain, according to official statistics, 229 workers were killed at work in 2007/8 due to accidents. Its relatively easy to gather this sort of information – its very difficult to hide the fact that somebody has been killed. But its considerably more difficult to obtain accurate figures on the number of people who die due to a disease they’ve contracted due to their work. As most industrial disease takes many years to develop the individuals may have moved job, or even retired. Some diseases can have more than one cause (some work related, others not) and its not always easy to decide exactly what caused it. So statistics on ill health at work are not absolutely certain. One fatal disease that is almost always work related is mesothelioma of the pleura, a cancer of the lung lining which is caused by exposure to certain types of asbestos. In 2006, two thousand and fifty six (2056) people in Great Britain died due to mesothelioma, almost ten times as many as were killed by accidents at work. (The numbers are increasing and are expected to peak at around 2450 deaths in 2015.) And that’s only one work related disease. There are others including other types of cancer, other lung diseases, such as silicosis, and diseases affecting other organs. On an international scale, the World Health Organisation estimates that there are around two million work-related deaths per year.

Of course not everyone dies from disease. Work related ill health can have other impacts on life, causing discomfort, pain and disability. Its difficult to obtain reliable statistics on this, but a survey by the UK Health and Safety Executive indicated that 2.1 million people in Great Britain suffer from an illness they believed was caused or made worse by their current or past work.

So ill health caused by work is a serious problem, even if its not as visible as the results of accidents at work. Occupational hygienists work to reduce the number of people affected. We do that by

  • recognising where there are potential problems that could cause ill health
  • evaluating the degree of risk – i.e. how serious the problem is in practice
  • finding ways to control the risk