The old corrosive fluxes were definitely bad for your lungs, and I used to wheeze a bit when doing a lot of soldering, but I was fine. These days, fluxes are pretty safe.
As for lead solder, I love the stuff. Been soldering for 45 years with 60/40 lead/tin. NO PROBLEMS!
The old TVs had a heat sink thermal compound containing beryllium oxide. Yep, used that stuff a bit in the early days. NO PROBLEMS!
Now the IBM old unit record machines (models 082, 083, 548, 557, 519, 514) which I used to work on when I first started at IBM contained capacitors containing polychlorobiphenyls. Highly carcinogenic and incredibly toxic. NO PROBLEMS!
Not the mention the myriad of toxic chemicals I used at IBM (tape cleaner), and that one of the IBM customers (Siemens in Richmond, Melbourne) has asbestos dust chunks falling from the ceiling and filling the fans and vents of the mainframe I occasionally had to vacuum out. NO PROBLEMS!
Oh yes, the IBM plant in Wangaratta. Carcinogenic bromides given off when a PCB caught fire. NO PROBLEMS!
At home I sprayed with Dieldrin, DDT, Roundup etc. I once sprayed my Holden 186 red motor in a tiny shed with lead-based red paint without a mask, coating my lungs with lead paint. Bloody idiot thought I was invincible. NO PROBLEMS!
...SO FAR!