Opinion only... Your mileage may vary... I ran into this type of question when I was about 19. I had worked in a couple of factories, dirty places with welding, glues, paint and such, and it didn't have a great impact on my health (it didn't hurt me either at the time.) I then worked for an ice cream delivery place. Climbing in and out of the refrigerated truck ended up giving me pneumonia, spent six weeks in the hospital. I then worked in an Operating room for 6 months, and then in med-surge/Emergency (all as 'orderlies', changing used linens, mopping floors, helping out.) That was ok. I then wanted to enlist in the Navy. They wouldn't take me, because of my CF. So, I ended up applying for assistance from the Government. They put me through some testing, and in my opinion, because I had worked in the hospitals, they suggested I work as a Dental assistant. I said, are you nuts, first time I cough into an open mouth, I'm history! They then said, the test show you can anything you want, what do you want to do? I said, Computers. Been in that business for over 30 years now.