Surveillance of suicide deaths involving gases in Australia using the National Coronial Information System, 2006 to 2017

Background: There have been concerns about the increased use of helium and nitrogen gas as a suicide mechanism in Australia. Methods: National Coronial Information System data were used to investigate gas‐specific suicides in Australia over the period 2006–2017. Characteristics were compared between helium or nitrogen, carbon monoxide and seven other gases. Results: Gas inhalation accounted for 10% (3,103/31,002) of all suicide deaths in Australia between 2006 and 2017. The mean age of individuals who died by suicide was 47.6 years (SD 16.9, R 14‐97) and 83.3% were male. The number of gas suicides declined over the study period (IRR=0.96). The fall was associated with a 47% decline in carbon monoxide suicides (IRR=0.93). There was an increase in deaths due to argon (IRR=1.60) and nitrogen (IRR=1.27). Compared to individuals using other non‐carbon monoxide gases, individuals who died by suicide from helium or nitrogen were significantly more likely to be older, have a physical illness and/or disability, have contacted a euthanasia group and have accessed instructional material and purchased gas online. Conclusions: Suicides by carbon monoxide decreased between 2006 and 2017 alongside an increase in argon and nitrogen gas use – particularly among older adults. The ease of access to these gases points to new targets for means restriction. Implications for public health: Identifying the types of gases used in suicide deaths and emerging trends may enable targeted interventions that could potentially reduce access.