|Firefighters inhale the smoke and get it in their lungs. It causes blisters, which break and run. The heavy particles of the smoke contain the poisonous resin; it falls down in soot form. When it's inhaled, the lungs swell, causing coughing and extreme irritation and swelling in the throat. It makes breathing near impossible, and can be life-threatening."
Firefighters who know or suspect that poison oak is being spread by smoke in the air should seek medical attention at the first sign of breathing problems. "It will be apparent if it's in the air," says Jeffries. "People will break out and encounter other problems. If it's a fire of any size, the medical unit leaders will be aware of it. They can detect symptoms of internal poison oak, and decide whether to treat or transport. Some people think they're immune, but poison oak should not be taken lightly."
****I found this info above on the web. It appears that if you feel any of the above symptoms, you should go to an ER right away. Since it has been 20 hrs. and you still feel okay, I doubt you will have the breathing problems. There is still time to see if you will break out on your skin somewhere (I hope not for your sake) Since you were "exposed" in a sense you should keep a watch for any symptoms. Most likely being in the cab with air filters running saved you from harm. God bless & good luck. [email protected]