Joint statement on nitrous oxide
NZSA, ANZCA and ASA release a joint statement on decommissioning nitrous oxide for medical gas pipeline systems
Anaesthetists continue to demonstrate leadership in decarbonising healthcare with ANZCA’s Environmental Sustainability Network (ESN) Executive Subcommittee developing a joint statement with the Australian Society of Anaesthetists (ASA) and the New Zealand Society of Anaesthetists – Ngā Ringa Tauwhiro o Aotearoa (NZSA).
This statement reflects a collaborative bi-national approach to nitrous oxide (N2O), one of the most potent greenhouse gases that contributes to climate change, and the healthcare contribution to its emissions that requires urgent and decisive action.
This joint ANZCA/ASA/NZSA statement on decommissioning N2O medical gas pipeline systems (N2O MGPS) aims to strengthen patient safety and environmental sustainability by promoting universal support for:
- Decommissioning N2O MGPS
- Avoiding installation of new N2O MGPS
- Utilising point of care cylinder supply where N2O is required for clinical use.
This statement does not propose to impact or change clinical indications for use of N2O.
Health New Zealand Te Whatu Ora’s (HNZ) Greenhouse Gas Emissions Inventory for the year 2023-24 lists medical gases and anaesthetic vapours as its fifth-highest emission source. It also calls out nitrous oxide as its highest direct greenhouse gas emission of all medical gases and anaesthetic vapours. HNZ reported a 17% reduction in emissions associated with N2O over the past two years, in its latest Greenhouse Gas Emissions Inventory Report. In part due to the decommissioning of reticulated systems to avoid leakage. A result of initiatives led by anaesthetists in New Zealand.
The statement is in line with the 2024 release from the United Kingdom and Irish Anaesthesia College and Associations, and the American Society of Anesthesiologists, advocating for decommissioning existing N2O MGPS and not installing N2O MGPS in new hospitals. Furthermore, in September 2025, the World Health Organization (WHO) added a qualifying statement to the emergency medicines list with changes to the listing of N2O and the recommendation for use of point-of-care cylinders.
This work is supported by ANZCA PS64(G) Position statement on environmental sustainability in anaesthesia and pain medicine practice 2019 (currently in review) and the ANZCA Council Statement on Climate Change.
The NZSA Environmental and Sustainability Network were instrumental in guiding the NZSA’s input towards this statement. Members of the ESN and anaesthetists across Aotearoa are leading the way in efforts to decommission reticulated N2O in their workplaces. As highlighted in recent articles:
- Removing the leaks: Decommissioning reticulated nitrous oxide, April 2025.
- How do you eat an elephant? Decommissioning nitrous oxide across Aotearoa, December 2025.
The ASA and NZSA’s support of the Environment and Sustainability Statement (2021) from the Common Issues Group (CIG) outlines the group’s recognition that the professional actions of anaesthesiologists have a significant environmental impact that may affect health and economies.
N2O is a topical item for anaesthetists and was included in the recent 2025 Blue Book titled Back to the Future: A return to point-of-care nitrous oxide cylinders (p289), along with the 2025 ANZCA Winter Bulletin article Tackling leaks from nitrous oxide infrastructure (p24-25).
The statement further strengthens anaesthetists’ commitment, actions and measures to minimise the health impact of climate change and promote environmental sustainability.
We recognise the need for urgent action on climate change, and mitigating the effects of anaesthesia gases on planetary health is one initiative of a wider comprehensive suite of strategies to do so.
Photo credit: Stephen Andrews
