Hello I have a COSHH related question. We have a design team who use spraymount. (an aersol type spray glue). In the exposure section of the MSDS for this product it quotes a max STEL of 1500ppm. I understand all about COSHH assessments, related PPE etc, but what I dont undertsand is how you know wheter or not you are exceeding the STEL and therefore exposing the employee to too much of the product? Is air monitoring the only solution? The problem I have is that our employees only use the product occasionally and surely air monitoring would be a bit OTT? How else can you determine if the STEL/ WEL or TWA is being exceeding? Or do you actually have to at all if its only occasional use? Please help! :)

If the product is used very rarely, for example 5 mins a day, once a week, would your suggested approach still be worthwhile?

I have become ill, and the substances that I use at work have caused it! You prove that it has not. What is the cost of a stain tube. Due diligence?

How rarely it is used can't have any bearing on whether the STEL is approached or exceeded - all that will affect this is how it is used, the volatility of the substance and the amount of it in the product (presumably it is an ingredient in the product rather than the product itself that has the STEL). I'm not sure what you mean by "max STEL" (it's lower STELs that are more of a concern!), but 1500 ppm is quite high, and you might be able to conclude that it was unlikely to be reached in all the circumstances. An alternative approach that might be more proportionate is to base your assessment on whether it is being used in accordance with the manufacturer's instructions.

Hi Stevel Its not that I oppose using a stain tube or any other measuring techinque...Im just not sure if this approach would be valuable or neceassry due to the very very limited use of the product... Im a firm beleiver in a less is more kind of approach in regard to safety where possible, we sometimes get a bad rap for over the top controls and approaches, However if someone with more knowledge and experience with me in the subject beleives measuring IS neceassry regardless of how often the product is used and reccomends so, I would happily do it.

I believe the material in question may be acetone. The STEL (15 min reference, ppm) does align with last EH40. I still concur with Chris - adequate ventilation in use.

I was told by a very experienced occupational hygienist that Drager stain tubes etc are only accurate to about 30% anyway, so not a particulary reliable way of judging if a STEL/WEL is being breached. At best a first stage indicator. Especially if operating close to the WEL/STEL limit. I would agree with Chris Packham - if the other controls are good, LEV/ventilation, working practices, short exposure time. Then the situation should be ok. The substance with the 1500ppm STEL/WEL might only be a small part of the overall compound, which is another point to consider. 1500ppm is quite a high STEL. Given all of the evidence, I think it might well be justified to conclude that the WEL/STEL is unlikely to be exceeded. The justification being the body of evidence available and, yes, the considered opinion of a competent safety adviser. Air sampling is unlikely to be needed. As others have indicated, not everything has to be done to reduce risk - so far as is reasonably practicable etc. Have you reached a justified conclusion for your CoSHH risk assessment?

Thank you all for the repsonses. It has been a great help

Below is an extract from Eh40 which may help. 8 Exposure should be recorded as the average over the specified short-term reference period, normally 15 minutes, and should be determined by sampling over that period. For short emissions of less than the reference period, which still may have the potential to cause harm, appropriate action should be taken to ensure that a ‘suitable and sufficient’ risk assessment is carried out to ensure that there is no risk to health from such exposures. Usage periods have been identified as around 5 minutes so IMHO neither limit is particularly appropriate (not even sure if you can get an accurate reading over such short time / concentration). Normal RA should cover this. If you are following the manufacturers instructions (good general ventilation) and their is no evidence of ill effects (no one is 'high' as described by Stuff4blokes!) then there should be no real problem. (I'd be more concerned about spraying it in the eyes and a strong degreaser (dermatitis) despite the ladies (and men) using it on the nails, though again given limited use this may not be a big issue. Hexane (n-hexane) is a different matter entirely, it has a very low WEL due to its long term irreversible effects (includes Peripheral PolyNeuropathy (nerve damage)). We use a wide variety of solvent and n- hexane used to be a common component. We have notices a great reduction in this (substitution with less hazardous at source by the manufacturer). (its not listed as constituent in this product). Come to think of it we were taught (20+ years ago) to clean up spills of this using sand (increases surface area - evaporation) and were known to be 'high as kites!' If I ever develop PPN I know where to point the finger!