Active on duty firefighters are more, likely to experience adverse effects from inhaling carbon monoxide much faster than non active off duty none smokers. This is because they are exposed to relatively high concentration of carbon dioxide and component smoke. Carbon dioxide has various baldheads like acrolein, phosgene ammonia and hyderocholric acid. Inhalation of highly concentrated carbon monoxide in smoke causes pathological sequelae which is a condition common in fire victims and fire fighters.
They are more at risk of acute ventilator function than the off duty firefighters. The firefighters have been found to have a greater loss of lung function; a condition caused by chronic and acute smoke inhalation (Emmanuel , SC,(2000), 175-82). The lung decreases in size and causes respirator symptoms associated with exposure automobile exhaust. A study carried out by Evans et all 1988 shows that there is no any difference in symptoms of respiratory except for a higher symptom prevalence in fire fighters who smoked because of the presence of high hemoglobin in the blood.
I have experienced a situation in which a truck emitted gases which was inhaled by passengers. Usually this emission has an approximate of 5 to 10 percent of carbon dioxide. This can be prevented if air/fuel ratio is measured, putting the right temperature within the engine before separating it, operating at excess deep, idling and raising the engine. The defects of the truck were leaky exhaust pipe, leaky manifold engine connection, leaky manifold pipe and leaky tail pipe. All these needed replacement.
Reference
Emmanuel, S.C.(2000) Impact to lung health of haze from forest fires: the Singapore experience. Respirology. p. 175-82