Surgical Suite » Waste Anesthetic Gases

The anesthetic gases and vapors that leak into the surrounding areas during medical procedures are considered waste anesthetic gases. It is estimated that more than 250,000 healthcare professionals who work in hospitals, operating rooms, dental offices and veterinary clinics, are potentially exposed to waste anesthetic gases and are at risk of occupational illness. The waste anesthetic gases and vapors of concern are nitrous oxide and halogenated agents (vapors) such as halothane, enflurane, isoflurane, and desflurane.


Exposure to waste anesthetic gases occurs from:

  • Leaking or poor gas-line connections.
  • Improper or inadequate maintenance of the machine.
  • Patient exhalation in the recovery room or Post Anesthesia Care Unit (PACU) during off-gassing of surgery patients.

Health Effects

Some potential effects of exposure to waste anesthetic gases are nausea, dizziness, headaches, fatigue, and irritability, as well as sterility, miscarriages, birth defects, cancer, and liver and kidney disease, among operating room staff or their spouses (in the case of miscarriages and birth defects).

Recognized Controls and Work Practices

Employers and employees should be aware of the potential effects and be advised to take appropriate precautions. A number of recognized controls and work practices are contained in OSHA's Guidelines for Workplace Exposures to Anesthetic Gases as well as documents contained in the Additional Information section below.

  • Use appropriate anesthetic gas scavenging systems in operating rooms.
    • Appropriate waste gas evacuation involves collecting and removing waste gases, detecting and correcting leaks, considering work practices, and effectively ventilating the room (Dorsch & Dorsch, 2007).
  • Provide enough ventilation in the surgical suite to keep the room concentration of waste anesthetic gases below applicable occupational exposure levels. Ensure that ventilation design and specifications meet the most current American Institute of Architect's Guidelines for Design and Construction of Health Care Facilities.
    • To minimize waste anesthetic gas concentrations in the operating room, the recommended air exchange rate (room dilution ventilation) is a minimum total of 15 air changes per hour with a minimum of 3 air changes of outdoor air (fresh air) per hour (American Institute of Architects, 2006).
  • Use a properly designed and operating dilution ventilation system to minimize waste anesthetic gas concentrations in recovery room areas.
  • Conduct periodic exposure monitoring with particular emphasis on peak gas levels in the breathing zone of nursing personnel working in the immediate vicinity of the patient's head in recovery room areas.
    • Note: Methods using random room sampling to assess ambient concentrations of waste anesthetic gases in the recovery room are not an accurate indicator of the level of exposure experienced by nurses providing bedside care. Due to the closeness of the recovery room nurse to the patient, such methods would consistently underestimate the level of waste anesthetic gases in the breathing zone of the bedside nurse. Therefore, use personal sampling to determine the employee's overall workplace exposure to waste anesthetic gases.
  • Implement a routine ventilation system maintenance program to keep waste anesthetic gas exposure levels to a minimum.
  • Turn off vaporizers of anesthesia machines when not in use. Proper face masks, sufficiently inflated endotracheal tubes, and the prevention of anesthetic spills will decrease the amount of waste anesthetic gases in the operating room.
  • Ensure that: inspection and maintenance of anesthesia machines are conducted by factory service representatives or other qualified personnel at least every four months; leakage of gas is less than 100 ml/min during normal operation; and employee exposure to anesthetic gases in use does not exceed NIOSH recommended exposure limits during normal operation,
  • Prior to each day's use, conduct a complete check of all anesthesia equipment (connectors, tubing, etc.).
  • Clean up spills of liquid anesthetic agents promptly.
  • Provide information and implement a training program in accordance with OSHA's Hazard Communication Standard [29 CFR 1910.1200] and any other applicable OSHA standards for all employees exposed to waste anesthetic gases.

Additional Information