Microbiological Events After a Fire in a High-rise Building

Abstract

Water used to control a fire on an upper floor in a highrise office building wetted furnishings and construction materials on lower floors and resulted in the amplification of microorganisms especially mesophilic and thermotolerant fungi. Concentrations of fungi in indoor air including Aspergillus, Penicillium and Paecilomyces approached or exceeded 104 colony forming units per cubic meter (cfu/m3). Airborne endotoxin levels increased about 1 order of magnitude over background levels. Sampling for fungi using both culture plate impactors and spore traps showed that spores were migrating from water damaged to undamaged areas in the office complex. Elevator shafts traversing water damaged floors likely provided the major dispersion pathway of spores into occupied areas. Construction materials such as plaster ceilings that had been wetted during the fire but were free of visual fungal contamination were found to be strong fungal reservoirs after the building had thoroughly dried. Management of microbial contaminants after a fire in a highrise building is an important public health concern and therefore an essential aspect of building restoration.