Can someone steer me in a direction to find out the OSHA rules on tag out procedures. I don't think I have 2 customers that do the same thing- they all seem to have their own procedures.

I had a customer tell me that they were in an OSHA safety meeting & the instructor said that I - as the vendor who services the equipment- am the one that's required to have my own locks/tags/ paperwork regarding any equipment tagged out at his facility. I've never heard of this- any thoughts?