Symptoms of “sick building syndrome” are usually vague and the source of the problem unknown. Such problems have hidden costs in lost productivity, sick leave, and medical costs. SEC performs thorough, systematic indoor air quality investigations. Investigations begin with a careful study of complaints and the work environment. Initial studies screen the most likely and most common causes of reported symptoms. Clients are informed of the goals, and of the results, at each phase of the study. SEC can identify problems linked to inadequate makeup air, chemical contaminants and pollutants, and bioaerosol.