My kids were playing around a bonfire that had poison oak in it (for about an hour). are they at risk for lung problems and how long before symptoms?

No: Skin reaction will be seen in a few hours if they are already allergic to it. If not allergic, there will be no reaction. If this exposure results in sensitizing for the first time you may see skin reaction in a week, especially on the face. Antihistamines are useless for this. Oral and topical steroids for a short time are very effective.

Soon: There are anecdotal reports of sensitivity to the rhus antigen by inhalation (smoke from fire) but these are few & not necessarily seen in those with skin sensitivity. If they occur, the reaction would be expected within the first few hours & produce wheezing & copious mucous flow.