It has been estimated that over 200,000 healthcare professionals may be exposed to waste anesthetic gases and are at risk of occupational injury. In 1977, the National Institute for Occupational Safety and Health (NIOSH) issued the publication: Criteria for a Recommended Standard....Occupational Exposure to Waste Anesthetic Gases and Vapors. This publication was based primarily on scientific evidence from human and animal studies suggesting that chronic exposures to anesthetic gases increases the risk of both spontaneous abortion and congenital abnormalities in offspring among female workers and wives of male workers exposed to waste anesthetic gases. In this recommended standard, NIOSH defines the recommended exposure limits (REL) for nitrous oxide and halogenated anesthetics. NIOSH recommended a time-weighted average (TWA) REL of 25 parts per million (ppm) for nitrous oxide over the period of administration. The REL for halogenated anesthetic gases is a ceiling limit of two ppm.In this study, waste anesthetic gas exposures to seven Post Anesthesia Care Unit (PACU) nurses were quantified during one day of air sampling within their breathing zones. Nitrous Oxide was sampled using a ChemExpressTM Personal Monitor (Assay Technology, Inc. Pleasanton, CA) attached to the nurse's lapel for approximately three hours. A total of 15 samples were collected. Isoflurane, desflurane, and sevoflurane were sampled using a ChemExpressTM Personal Monitor (Assay Technology, Inc. Pleasanton, CA) attached to the nurse's lapel for approximately three hours. A total of 15 samples were collected. In addition, Isoflurane, desflurane, and sevoflurane were also sampled using Anasorb© 747 sorbent tubes (SKC, Inc. Eighty Four, PA) to compare the passive and active sampling methods. The tubes were attached to the nurses lapel for one hour. A total of 15 samples were collected. The exposures to nitrous oxide and halogenated anesthetics were below the NIOSH RELs. An Analysis of Variance (ANOVA) showed a statistically significant difference (p < 0.05) in the active and passive sampling methodologies.