In the past two years, serious allegations were made by former National Gallery of Australia (NGA) contractors and staff concerning threats to public health and the collections from the heating, ventilation and air conditioning (HVAC) infrastructure installed when the building was opened in 1982. This paper discusses the investigation undertaken with an independent consultant following extensive parliamentary and media attention, focusing on aspects relating to damage to collections. The communication required between the consultant (a mechanical engineer) and NGA building services personnel, conservation and executives is discussed. The analyses conducted included measuring concentrations of hydrogen peroxide during the cleaning and operation of air-handling units and measuring various pollutant gases at the parts per billion by volume (ppvb) range throughout the 20,000m2 building. The investigation concluded that no damage was caused to the collection by the HVAC system, but raised numerous questions relating to development and application of standards for air quality in museums. -- SCMRE