Ok so you have a process which might lead to people being exposed to substances hazardous to health. COSHH requires that you manage this process using a risk assessment. The first step of  the risk assessment would be to identify all of the hazardous substances used in the process. Do you have SDS’s for the pharmaceutical ingredients and gases?  Do any of the substances have WELs as defined in EH40 is there any information “out there” about these substances?

Based on that you need to make a judgement call as to whether exposure to these substances constitutes a hazard to your employees. You then need to look at how the process will worsen the effect of the substances, creating a greater risk of exposure. Will it create an inhalation risk, absorption through skin or mucous membranes risks, an ingestion risk or even an injection risk.

Then you need to decide on the controls: do you need to completely isolate the process so nobody can come into contact with the substances? What would you do about  maintenance work when you may have to turn off some or all of the controls? If you can’t     completely isolate it will you be relying on LEV? Is it the right LEV for this purpose? Will you arrange for the LEV to have its statutory testing? Against what standard?  What administrative controls will you have? Will you enable and make staff wash their hands after working with these pharmaceutical products? Will you regularly check the gas lines from the cylinders for leaks? Will you have a low oxygen monitor in case an asphyxiant gas leaks out? Nasty gases often have a smell added but if these  gases are going to be used to deliver drugs, then you don’t want any sort of smell from them. Will you measure levels of hazardous substances  in the atmosphere in the work area? Will you carry out health surveillance of  staff working in this area?

Having considered everything will you tell employees to use PPE? Will you make sure that the PPE fits them and that they are wearing it correctly?

What will you do if it all goes wrong ; what the plan if there is a fire or a massive leak? What is the clean up procedure?

And of course finally how will you inform and train your staff so they do all of this  correctly?

As you can see COSHH is very easy! Sorry about the info dump, but it what comes out if I hear the word COSHH.   

As someone closely involved with COSHH for years I agree completely with AK. What is important is that the COSHH assessment is for the specific task. What happens during the task? What chemicals are used (and remember that they may not have or be on a safety data sheet)? What happens to them when they are used and what are the resultant hazards? These can be significantly different from what you started with and what is on that SDS. What is the actual/potential exposure to these hazards? Could exposure by different routes (inhalation, ingestion, dermal) be cumulative or synergistic? Could this affect the significance of compliance with the WEL? (Studies have shown that facial skin exposure at below the WEL can, with some chemicals, cause damage to health and thus require appropriate exposure management.) What is the risk of damage to health from the exposure? How will you manage this? How will you then monitor that your COSHH management strategies are working? (Health surveillance anyone?). What will you do if there is an unseen event that causes an unexpected exposure?

In my view COSHH essentials cannot do this. As is stated by HSE COSHH essentials can only create a generic risk assessment that cannot take into account the many variables that can occur during a specific task. 

COSHH Essentials is very basic and as you say is not set up to deal with compressed gases.

So you would need to go back to first principles for the COSHH assessments.  This probably means arranging some training for the people doing the assessments.

Having said that, most COSHH assessment training is rubbish so you would need to shop around for a good one.

There are also the various commercial online COSHH assessment services, but they are set up just to give you impressive-looking, lengthy documentation hiding a generic risk assessment that doesn't take your process into account.

I don't think there are any short cuts to this, which is why you may find all of the responses unhelpful.

Not knowing exactly what you are doing makes it difficult to tell you anything specific. As Chris said COSHH essentials is something for routine work activities. What you seem to be taking about is a technical process and COSHH essentials  is not really intended for that: you should be starting from first principles and given what you say you may be working with it is important that you get this right. It is also not clear whether you are talking about something new  or something that you have been doing for some time. If it is an established procedure, what are the current risk assessments based on if not COSHH?    

Edited by user 19 November 2021 15:45:14(UTC)  | Reason: spellings

...you can only go so far with COSHH essentials...your industrial hygienist should be able to guide you since it is API..which OEB?..that will dictate the containment measures - mechanical, ventilation, maint, and PPE...HFA inhalation would be main route so repiratory..

this gives some sense of the toxicology on it but I would refer to your IH support in house...drop me a pm if you need to...

https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.858.7291&rep=rep1&type=pdf

As an addendum to my comments I recommend taking a look at section 6(4)-2 of the Health and Safety at Work etc. Act and ask yourself whether the standard safety data sheet really provides the information that this part of the Act requires.

Edited by user 23 November 2021 18:35:51(UTC)  | Reason: Typo