I hate to say it, but a 150 might just be too heavy, but not knowing your local construction code, not knowing how the floors were constructed, I can only guess...
I wouldn't take the risk though. It may never fail, but you have to think about what happens if it does.
That's a lot of weight. I think it would make me too nervous without a structural engineer giving it the okay. I'm sure the 1st floor tenants would agree.