Presence of thermophilic acintomycetes in residential heating systems.

Thermophilic actinomycetes, associated with a hypersensitivity pneumonitis, may be found in compost but also have been detected in heating systems of office buildings. This study was designed to determine whether these organisms were present in residential heating systems. Furnace dust or humidifier water of 12 of 20 homes contained thermophilic actinomycetes, indicating that the organisms may be found in areas other than specific decomposing organic dusts.