The NIOSH standard of a 2ppm exposure limit to halogenated anesthetics and 25ppm of nitrous-oxide (10024972) is given as well as recommendations for control procedures and work practices, medical surveillance, labeling and posting, fire and explosion hazards, and sanitation practices, educating employees, monitoring and recordkeeping. In addition, the criteria used for establishing the standards are provided. The exposure limits for specific halogenated anesthetics are (in milligrams per cubic meter) 9.76 for chloroform (67663), 10.75 for trichloroethylene (79016), 16.15 for halothane (151677), 13.5 for methoxyflurane (76380), 15.1 for enflurane, and 10.31 for fluroxene (406906). It is stressed that the recommendations in the safety rules should not preclude proper patient care and safety practices, particularly if patient needs arise that require deviation from the recommended safety standards. Criteria include the biological symptoms of exposure such as decreased performance, optokinetic nystagmus, cognition and physiomotor decrements, headache, fatigue, nausea, spontaneous abortions, cancer, premature deliveries, congenital anomalies, infertility, liver disorders, kidney disorders, eye disorders, decreases in male birth, animal toxicity, and epidemiologic evidence; biologic evaluation of exposure including sampling and analysis methods; and inhalation anesthetic techniques and sources of waste anesthetic gases. Tables give physical and chemical properties of anesthetics, anesthetic gas concentration in locations with and without waste gas scavenging, statistics on hospitals using anesthetics, and figures illustrating various types of instrumentation for control measures. Analytical methods for determining concentrations and for sampling are given.