Medical, dental, and veterinary professionals who work with nitrous- oxide (10024972) (N20) may be at risk for serious health effects due to their exposure. Human studies indicated that exposure to N2O may cause reduced fertility, spontaneous abortions, neurologic, renal, and liver disease, decreases in mental performance, audiovisual ability, and manual dexterity. Studies on exposure to N2O in animals during gestation indicated that such exposure can adversely affect offspring. The use of N2O scavenging systems can protect workers by venting unused and exhaled gas away from the work area. Recent studies indicated that use of these systems significantly reduced the risk of impaired fertility among female dental assistants exposed to N2O. However, even with these scavenging systems in place, N2O exposure levels can still be high as evidenced in a recent NIOSH Alert Report showing N2O exposures 12 times higher than the recommended limit in hospital operating rooms and more than 40 times the limit in dental operating rooms. Additional steps to reduce N2O exposure in the workplace included: monitoring anesthetic equipment every 3 months for leaks, monitoring air in the workers personal breathing zone, monitoring the environment, preventing leakage from anesthetic equipment through proper maintenance and inspection, using a scavenging system that includes securely fitting masks, sufficient flow rates, and properly vented vacuum pumps, adequate room ventilation (increasing airflow into room), using supplemental local ventilation to capture N20 at source, and implementing an education program describing N2O hazards and prevention measures.