Welcome, my name is Rick and I will do my best to help you with your issueDo you need the NYC code referenced? if you do I will opt out since I don't have access to it but any modification to the mechanical systems particularly in a commercial setting ALWAYS requires a permit in any jurisdiction
Do I understand correctly that you are saying that if electrical work was done, plumbing fixtures installed and HVAC work performed, that all of that would constitute modifications to mechanical systems?
Absolutely, not to mention you have handicap accessibility issues here. But I don't see how this is OSHA related. This looks like a building code violation.
OSHA regulates job site safety issues.
Occupational Safety and Health Administartion
do you have any more questions?
If you want to file a complaint you should probably contact the city's code enforcement department