I think the easiest solution is to hire a lead and asbestos testing company to perform a survey of your entire building. That way you can authoritatively respond to your Super's hesitancy. As a bonus, you could also be made aware of the much larger issue of needing lead and/or asbestos abatement. Either could be a very time-consuming, disruptive, expensive project, and the sooner you find out about it, the better you'll be able to plan and budget for it.

I've found that "making excuses" is not limited to union members. Either your employees act professionally and responsibly or they don't. Being a union building works both ways. If you strive to maintain good relations with your union there's a lot they can do for you. This is not always possible given individual human nature, but I've found comity usually works better than confrontation.