How do smoke particles and soot cause cancer risk, and how small are these particles?

99% of smoke particles collected during overhaul were less than one micron in diameter. 97% were too small to be visible. Soot contains polycyclic aromatic hydrocarbons (PAHs), accelerants, acroleins, and volatile organic compounds (VOCs). Skin absorption increases 400% for every 5°C rise in skin temperature, making firefighters highly vulnerable when hot.