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#1 Posted : 15 June 2017 11:08:36(UTC)
Rank: New forum user

Hi All,

I'm looking for some advice or rational regarding exposure levels. I have a product with a number of constituants which have WELs (standard stripper, nothing exciting). 4 componants within the product have been identfied as having WELs. all 4 individually have been listed as between 0.05% and 10% of the compition of the product

This substance is rarely used, and when used the instruction is to wear a mask, well ventilated area and usually would be no more than 250ml - 1L at a time.

Now I have been asked how we would determine the exposure levels to those workers using the product. G409 says air sampling is the only way to do this but it seems to me like overkill. what rational can be applied to show that exposure in these quantaties for this substance would not be likely to be above WELs.

Please note my question isn't regarding calculating the exposure dose to the person after monitoring as i understand this. it is how I can show monitoring would not be required in the first instance based upon raw data in the SDS, the control and the use.

Im sure the same could be applied to many 'household' products which have WELs listed within their composit ingredients but are used in small quantities for short duration (graffiti remover, WD-40, line marker) Surely air sampling cant be the answer to all of these cases.

Edited by user 15 June 2017 11:10:55(UTC)  | Reason: missed word

Ian Bell2  
#2 Posted : 15 June 2017 11:33:20(UTC)
Rank: Super forum user
Ian Bell2

Continue as you are. Make a logical argument and justification for you decision as you have started to do. 1. We substances are a low % content of the substances 2. Quantity is small 3. Time of exposure is 'rare' can this be further quantified in terms of time 4. Ventilation is good - natural or artificial? Air changes per hour? 5. PPE show what the specification is? 6. Training records/competence of personnel involved. 7. What is the hazard classification? Toxic/irritant etc 8. Is the substance used as a liquid or sprayed? If liquid what temperature is it used at? Obviously the higher the temp the more is likely to be released. Any further action required? Change of work process? Substitute for less hazardous substance? Use Lev?
thanks 1 user thanked Ian Bell2 for this useful post.
howieuk1878 on 15/06/2017(UTC)
#3 Posted : 15 June 2017 12:52:59(UTC)
Rank: Forum user

Why not do a CoSHH assessment or is that not too obvious?

Plus if the controls are in place there is no exposure, zip, nowt so theres your figure.

#4 Posted : 15 June 2017 13:40:42(UTC)
Rank: New forum user

Thanks Ian,

3) 30 minute exposure weekly; 1 person exposed 4)Good natural ventilation and air flow in large building 5) Type A filter. 7) Irritant 8)Liquid Form; used at ambient temperature

BigMac1 - The COSHH assessment has been completed and that outlines the controls used as above, however we were still asked "because of the identfication of WELS, how we determine the exposure leves to workers using the substance"

I guess the point im trying to establish is "i am sure we would be below, but how do i justify that other than through monitoring"

Dont get me wrong im not adverse to monitoring where there is a genuine call for it but for scenarios like this one it just seems un justfied.

#5 Posted : 15 June 2017 14:32:57(UTC)
Rank: Super forum user

WELs are for airborne contaminants, so for them to have any relevance the substance has to enter the body through inhalation. The ways this can happen are very limited. Is the substance or mixture volatile ie likely to give off  harmful vapours? Is it in the form of a powder that can be carried on air currents. Is it a liquid that can become aerosolised? If so how viscous is the liquid? In the process you are assessing is the substance decanted from one vessel to another? Does it become agitated by stirring or as a result of a chemical reaction? What happens when the susatnce is spilled? What are the cleaning processes involved?

An example would be an adhesive that contains MDI (methyle diphenyl diiosocyanate) which is a very commonly used substance. MDI is a powerful respiratory sensitiser and has recently been categorised as a suspected carcinogen, but in its natural state is a solid. It is normally part of a 2 pack adhesive and is usually, but not always, a very viscous mixture. Even though this has a workplace exposure limit it would be very difficult for the MDI in this sort of mixture to get into the atmosphere. The msds would show the WEL but in the form you would be using it the risk would be very low.

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