In hospitals, patient care facilities and even dentist offices there are medical gases that are used for patient care, inhalation therapy and even invasive surgery.  These gases if leaked into the ambient air of the facility could be harmful to other patients and medical staff.

Medical grade oxygen is used for patient comfort during procedures and for inhalation therapy.  The typical oxygen content of ambient air is about 20.9%.  Even though it is essential for human life, in concentrations that vary from 20.9% the mixture could be harmful; low levels of oxygen in blood cells, hypoxemia, could cause irreversible damage cells, prolonged high levels of oxygen can cause damage to the lungs.

Gas OEL (ppm) TWA STEL (ppm) IDLH (ppm) LFL/UFL Alarm (ppm) Application
Nitrous Oxide (N2O) 25 25 Dental / Medical surgery
Carbon Monoxide (CO) 35 1,200 12.5% / 74% 10 Monitor for patient comfort
Carbon Dioxide (CO2) 5,000 30,000 40,000 500 Incubators, Patient / Personnel safety
Oxygen (O2) Low alarm 19.5%, high alarm is at 23.5% Inhalation therapy
Medical Air (Detect CO content) Alarm level at 10 ppm for CO content of medical air Medical instruments, patient comfort

Summary of Medical Gases; exposure and alarm levels.

There are other medical gases that could adversely affect patients and personnel in medical or dental facilities;

  • When ventilators are used in patient care there can be elevated levels of CO2 in the patient and medical personnel spaces.
  • Nitrous Oxide is the primary gas used for patient comfort during invasive surgery or dental procedures. Leaking NO2 in surgery rooms could cause problems for medical personnel or unintended patient exposure.
  • Carbon monoxide monitoring in medical air applications – air driven instruments – in dental procedures could affect the patient and medical personnel.


Gas Type Multi-Zone Single-Zone PGM-IR MGS-400 Series MGS-550
Nitrous Oxide (N2O)
Carbon Monoxide (CO)
Carbon Dioxide (CO2)
Oxygen (O2)
Medical Air (Detect CO content)
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