CoSHH Regs will give the general requirements for assessing hazardous material, including health assessments.

For more specific info, what does the current version of EH/40 say and the associated WEL data?

The regulation would be CoSHH.

EH40 2011 did adjust the Short Term Exposure Limit for Chlorine.

In the ECHA web site under "Information on Chemicals" there are 5 registrations for Chlorine with one a full submission - under both the GHS and DPD classifications for Health Hazard "Respiratory Sensitiser" data is listed as "conclusive but not sufficient for classification".

So there is research indicating potential but there would be nothing definitively published for a lung function check at 6 month intervals - ask your provider for the specific lines from the regulation.

I do have a respiratory sensitiser at site - our OH Lung Function screening is each employee every 12 months however the provider attends twice a year so that we can fit in the necessary appointments and follow up if anyone is down with a cold / hay-fever etc.. on their scheduled appointment day

MSDS have R & S phrases / SDS have H & P phrases

Unless there was actual evidence of exposure to chlorine gas I would not expect staff to undergo any sort of lung function test. Chlorine from at I remember has serve acute effects but limited evidence of any sort of long term effects( which is what the lung function tests are supposed to test for)
You need to ask their criteria for these tests. These should derive from the requirements of reg 10(Monitoring exposure at the workplace) and 11 of COSHH(Health surveillance) and in particular what it says in the ACOP.

I have experience of managing respiratory sensitisers, specifically subtilisin enzymes used in the detergent industry. The problem with sensitisers is that even very small amounts of exposure can result in sensitisation, and it can happen at any time. A person can be exposed for years without any effect and then suddenly become sensitised, or he/she can become sensitised after one brief exposure. Lung function testing would indicate any loss of lung function but would not be a definitive indicator of sensitisation. The method in the detergent industry for checking for sensitisation is the use of 6 monthly skin prick testing. This would not be appropriate for chlorine but maybe urology would. Lung function testing could support this regime but definitely would not replace it.

Having re-read my post what I meant to say was that chlorine gas does not seem to have any cumulative effects ie the health effects from a small amount of gas does not build up over time. The main issue with chlorine is it’s acute ( potentially very serious ) effects. Lung function test would not on the face of it provide anything useful in relation to controlling the exposure to chlorine gas. What you would need is atmospheric monitoring and a robust system to control leaks.

Hi Leadbelly,
Agree about the nature of sensitisers, but Chlorine is not one of them: it is a respiratory irritant, albeit a very nasty one.

Employees that I have worked with and who have accidently, (but very briefly) cracked open a valve on a Chlorine cylinder never need to be told again to wear BA when changing cylinders in the future.

PH2

Have fun.
Full lung function tests are unpleasant and expensive.

I would suggest, if you have recently changed OH provider and the new provider thinks Cl2 is a respiratory sensitizer, you should probably change to an OH provider that knows what they are talking about.

From what you have written, it seems you understand Cl2 really quite well.