Well in the case of Mt Lebanon Pa. they saw an apartment building boom in 1940's thru 60's so in many cases you have electrical and mechanical systems in buildings getting well over 50+ years old. If they have not been updated and they need more rigorous inspections,
I received a call from an apartment building owner to check his generator. No problem I arranged to check the generator for hm it was a 60's era Onan Generator which was kept in very good shape and when I started it up to check it I was worried that some of the exhaust piping was going thru the ceiling and could not be inspected for leaks .
So I performed a simple back pressure test on the piping by closing it off which should have caused the generators motor to want to stall . It did not and to mine and the building owners horror I found that when the piping on the outside of the building was extended to prevent Co From building up in the building and blow it out to the back lot it was improperly installed and leaking deadly Co Gas right back into the building via the air inlet duct work which brings fresh air into the building.
and support clamp they lazily and dangerously used the tee and flange to support the pipe. The problem the flange has a hole thru it aprox. 1 inch in diameter so the exhaust gas goes down the short tee section thru the flange and into the brick and gas leaks out from behind the flange right into the air intake for the generator.
You can see the water stains from condensate which builds in the pipes when they sit leaking from the fitting because it is not sealed.
Now Mt Lebanon has been to the building a couple times over the years when power has been out a long time for a CO build up . But firefighters attributed it to the generator was running so long and yes this would be an obvious conclusion as it does happen especially with these old gen sets which do not burn as clean as new units which sit outside. No one not even myself would have expected such a dangerous and lazy hack was done to this piping but it was and it just goes to illustrate why generators need inspected not only in Mt Lebanon but state wide there are many generators sitting in basements of buildings which have never been properly inspected in decades waiting to kill people.because they have not been properly installed and maintained.