From what I understand, the Australian equivalent of our OSHA is a lot more strict/draconian in what they are allowed to do with an employer's workplace. Regulations in the US are not nearly as strict, at least as far as the 'we are allowed to come into your space' sense.
I found this if it helps:
I had someone come to my office, he was nice enough but he said he was from this company test and tag. He noticed that i had not had my stereo equipment tested and tagged. I take this with me as a DJ. he told me depending on the states you visit with in Australia that you have to have it tested and tagged as a DJ. ( occupation health and safety legislation ) is this right? and if so, why wasn't i told about this by government or something!?
i have been doing this for 10 + years and never heard that you have to have your stuff tested. He said it would apply to extension cords used in clubs/events that belong to me also.