The poster was talking about taking the POSS, a test, as an HP I've never been required to pass.
Ok, try....'study and pass' for the respirator test, go to your Fire Brigade training (at many sites operators are on Fire Brigade), spend a whole day humping hoses and combustables around, strap on the SCBA, go into the real live building with real life smoke, your airways already stressin from exertion plus now the dry air in your AirPak, and pass out for real from low O2 sats. Now, not only is YOUR life in danger, but the two other guys who are in the real fire dragging you out. It is irresponsible, and really fraudulent, to try that.
Not on Fire Brigade? Okay, try a rubber suit and respirator in the heat of sunny Region IV-nia , doing an ammonia onload. Exertion, ammonia fumes...same failure mode.
Either way, the physical exam is not there to keep eager deserving people from having fun in a lucrative career path, it is there to ensure that you can safely perform the essential functions of the position. Safe for you, safe for the company.
With that said, best of luck !