This article presents the study of a surgical block with serious deficienci
es of Indoor Air Quality (IAQ) located in the Hospital del Rio Hortega (Val
ladolid, Spain). Block characteristics were identified and symptoms reports
collected from 118 workers. At the end of the initial investigation, it wa
s concluded that there was Sick Building Syndrome. Measurements of ventilat
ion and contaminants were made of indoor air (CO, CO2, TVOC, anaesthetic ga
ses, at six differents points simultaneously) and outdoor air (hospital inc
inerator). Studies with trace vapors (Xylene) were also performed on instal
lations which crossed the surgical area to see whether a relationship exist
ed between the different surgical areas studied and other areas of the heal
th centre. Actions on contaminating foci, climatization-ventilation and per
sonnel training were finally recommended to Administration to solve the pro
blem. (C) 1999 Elsevier Science S.A. All rights reserved.