WFSA calls for the deactivation of central piped systems and a shift to portable cylinders to dramatically cut waste while maintaining safe, clinically appropriate patient care.
Nitrous oxide (N2O), a gas commonly used as an analgesic, anxiolytic, or adjunct anaesthetic, is used extensively in hospitals and clinics worldwide. However, recent studies have shown that up to 99% of the N2O purchased by a facility is regularly lost to the atmosphere through inefficiencies and leaks in the central piped (reticulated) delivery system, far outweighing the amount that is used for patient care.1
N2O is a potent greenhouse and ozone-depleting gas, with a long atmospheric lifetime and a global warming potential nearly 300 times that of carbon dioxide.2 Considering the significant environmental consequences of its release, the unnecessary emissions stemming from the standard central piped delivery system represent a significant opportunity for reducing healthcare pollution through targeted infrastructure modifications.
Decommissioning central piped N2O and transitioning to smaller, portable cylinders for point-of-care use is feasible and effective at mitigating waste. Such transitions have been successfully implemented at multiple healthcare facilities across the globe, including in the UK, Australia, Kenya, and the United States.1,3–6 Studies consistently report a 75-90% decrease in N2O purchase and emissions after transitioning to a portable supply, with no impact on the clinical availability of N2O or quality of patient care. This transition is further supported by a growing body of professional societies worldwide that call for the decommissioning of piped N2O along with advocacy at the individual, institutional, and government levels to align with modern environmental and safety standards.7–10
WFSA recommends the following actions to reduce global healthcare-related emissions:
1) Transition to portable N2O cylinders for point-of-care use in locations where N2O is deemed essential for clinical practice.
2) Deactivation of all central piped N2O delivery systems.
3) Omission of central piped N2O infrastructure from design and construction of new and renovated facilities.
While it is recommended to avoid N2O use if clinically appropriate and feasible, and use is decreasing in many facilities with the rising adoption of total intravenous anaesthesia and low-solubility volatile anaesthetic agents,11 many healthcare facilities still rely on N2O due to its low cost, accessibility, and safety profile, and use beyond anaesthesiology. N2O is commonly used in dentistry, and there is considerable geographic variation in its use in midwifery and paediatrics, with increasing use in these specialties in some countries.12 Thus, it is important to emphasize that the transition from central piped N2O to portable cylinders represents a shift from high-volume waste to low-volume precision point-of-care use as opposed to elimination from clinical care. These recommendations are consistent with the WFSA-initiated changes to the WHO Essentials Medicines List.13
References
1. Chakera A, Harrison S, Mitchell J, Oliver C, Ralph M, Shelton C. The Nitrous Oxide Project: assessment of advocacy and national directives to deliver mitigation of anaesthetic nitrous oxide. Anaesthesia. 2024;79(3):270-277.
2. Prather MJ, Hsu J, Deluca NM, et al. Measuring and modeling the lifetime of nitrous oxide including its variability. J Geophys Res Atmos. 2015;120:5693-5705. doi:10.1002/2015JD023267. Received
3. Chakera A, Waite A, Marchant A. Establishing system waste of piped nitrous oxide: Lothian nitrous oxide mitigation project. Anaesthesia. 2021;76:15.
4. Seglenieks R, Wong A, Pearson F, McGain F. Discrepancy between procurement and clinical use of nitrous oxide: waste not, want not. Br J Anaesth. 2022;128(1):e32-e34. doi:10.1016/j.bja.2021.10.021
5. Chesebro BB, Gandhi S. Mitigating the systemic loss of nitrous oxide: a narrative review and data-driven practice analysis. Br J Anaesth. Published online 2024:1-6. doi:10.1016/j.bja.2024.08.028
6. Morgan G, Ip V, Muret J, Loh PS, McClain CD, Gandhi S. Nitrous oxide waste and why we should abandon reticulated delivery systems. Best Pract Res Clin Anaesthesiol. Bailliere Tindall Ltd. 2024;38(4):305-311. doi:10.1016/j.bpa.2025.01.001
7. Mwangi D, Kugele M. Decommissioning Piped Nitrous Oxide in Health Care Facilities. Alliance for Transformative Action on Climate Health (ATACH). Accessed February 14, 2026. https://www.atachcommunity.com/resources/first-wins-library/reducing-nitrous-oxide-emissions-and-waste/decommissioning-piped-nitrous-oxide-in-health-care-facilities/
8. American Society of Anesthesiologists. Statement on Deactivating Central Piped Nitrous Oxide to Mitigate Avoidable Health Care Pollution. 2024.
9. Association of Paediatric Anaesthetists of Great Britain and Ireland. Statement on the Removal of Pipeline Nitrous Oxide. Accessed February 15, 2026. https://www.apagbi.org.uk/news/latest-news/post/4-statement-on-removal-of-pipeline-nitrous-oxide
10. European Society of Anaesthesiology and Intensive Care. Sustainability in Action: Committee Priorities, National Progress, and Emerging Initiatives. Accessed February 15, 2026. https://esaic.org/sustainability-in-action-committee-priorities-national-progress-and-emerging-initiatives/
11. Elliott K, Pierce J. Twelve-year trend in nitrous oxide use at a tertiary institution: striving for a net zero NHS. Anaesthesia. 2021;76(12):1667-1668.
12. Balmaks E et al. BJA, 2026;136(1):74-85. The role of the anaesthetist in mitigating the environmental impacts of nitrous oxide: a narrative review.
13. 25th WHO Expert Committee on Selection and Use of Essential Medicines Expert review, C.6 Nitrous oxide – EML and EMLc. Accessed February 15, 2026.
