On June 2, 1993, the National Institute for Occupational Safety and Health (NIOSH) received an employer request to conduct a health hazard evaluation (HHE) at the Hodges and King, DDS, dental office in Atlanta, Georgia. The request asked NIOSH to evaluate employee exposures to nitrous oxide (N 2 O) during administration of this anesthetic gas to patients. The request was prompted by a previous NIOSH HHE (HETA 93-0622) conducted to assess general indoor air quality at the dental office. This Health Hazard Evaluation (HHE) report and any recommendations made herein are for the specific facility evaluated and may not be universally applicable. Any recommendations made are not to be considered as final statements of NIOSH policy or of any agency or individual involved.