NIOSH conducted a survey at the Mifflin International Alternative Middle School in response to a request by teachers who were concerned about the adequacy of the ventilation in their work areas and about symptoms they were experiencing at work. The questionnaire that NIOSH distributed to employees at the school on April 28, 1993 showed that many employees had frequently experienced symptoms (e.g. fatigue, dry skin, headache) while in the building. A significant proportion of the symptomatic employees reported that their symptoms tended to get better when they were away from the building. Forty-eight percent of the Mifflin Alternative Middle School employees reported having frequently experienced one or more such ''building-related'' symptoms during the 4 weeks preceding the administration of the questionnaire. Environmental measurements of CO., T, and RH were generally within the guidelines recommended. However, midday and afternoon C02 concentrations exceeded, in some areas, the 1000 ppm guideline used to determine the adequacy of ventilation. Potential environmental contaminants found in the school included the natural gas used in the home economics room, environmental tobacco smoke, and compounds related to the storage of petroleum products. The impact of these contaminants, however, was on the immediate surrounding areas and no sources of indoor contaminants that would be suspected to cause most of the reported symptoms were identified during environmental inspections. Reports of building related health complaints have become increasingly common in recent years; unfortunately the causes of these symptoms have not been clearly identified. As discussed in the criteria section of this report, many factors are suspected (e.g. volatile organic compounds, formaldehyde, microbial proliferation within buildings, inadequate amounts of outside air to dilute the products of human metabolism, etc.). While it has been difficult to identify concentrations of specific contaminants that are associated with the occurrence of symptoms, it is felt by researchers in the field that the occurrence of symptoms associated with presence in interior environments can be lessened by providing a properly maintained interior environment.