Alternatively, could you try a set of 'made to measure' ear plugs? These are very good and reduce the ambient noise that causes damage but will allow you to hear your colleague perfectly well.
These are used with some success in KLM (who insist on using a crappy Telex lite headset in a noisy cockpit) and they do seem to stop the nasty noise. I don't know how much they cost exactly as mine were provided, but I think they are circa £150 to have them made. It is the filter within them that is important and the fact that they are fitted to your ears means there is no noise leakage.
I am sure this would satisfy your company SOP.