Holy shit, I had something like that happen to me a while a while ago... Only we were living in a basement apartment... The people moved out and at 7am we heard some real loud noises... Then, there was this overpowering smell... Like burning wood and varnish... I was passing out and taking seizures from it and our room mates had to leave because the chick there got a migrane from it.

Baiscally, the landlord hired people to sand the hardwood flooring throught the whole house upstairs and revarnish it....

We didn't hear shit about it, no letter, no noice, no warning.... To top it all off, the vents that were attached to our ceiling, connected to the upstairs floors so all the fumes and wood shavings came vented out to us... there were airvents above our beds....