9. Respiratory Disorders

The lung is the organ of first contact with inhaled hazards and is structurally vulnerable to effects of gases and particulate matter. Firefighters are selected for fitness and even if they have a history of asthma or atopy it is never more than mild on entry into the fire service. They also smoke much less than the general population. Much of the older literature suggested that firefighters do not have adverse respiratory outcomes except in severe cases of smoke inhalation, but this has been contradicted by more recent and better-designed studies. Firefighters often experience airways reactivity with severe drops in lung function and oxygen delivery immediately after smoke exposure during fire suppression, however this effect is usually quickly reversible, within hours. Intense exposure and smoke inhalation, especially to combustion products in fire situations involving synthetic materials, may also cause much more severe acute lung disease, which is sometimes irreversible. Chronic respiratory disease is generally uncommon but career firefighters appear to lose lung function faster than people in the general population and appear to be diagnosed with asthma more often, although the actual condition may be closer to a bronchitis. Firefighters do not have a marked elevation in chronic respiratory disease resembling “chronic obstructive pulmonary disease”, such as would be expected in cigarette smoking. Cigarette smoke and fire smoke are not identical and the latter may be more likely to cause acute bronchial irritation rather than small airways changes over time. Firefighters also smoke less, in modern times much less, than the general population. The weight of evidence at present supports the conclusion that individual firefighters may be at risk for disabling lung disease following specific, acute events associated with extreme exposure, which may interact with individual susceptibility, such as atopy. For chronic lung disorders, the picture is more complicated than conventional intrinsic asthma and is not well characterized. A large longitudinal study of firefighters would clarify this but not for many years. Use of self-contained breathing apparatus (SCBA) is highly protective but is difficult to sustain during the period of "overhaul", after fire suppression, when some toxic exposures peak or remain high.