Researchers are calling for tighter controls on sodium nitrite after a study identified a concerning pattern of suspected poisoning deaths involving the widely available food-preservation chemical.
A new analysis published in BMJ Public Health has raised concerns about the use of sodium nitrite in intentional poisoning deaths in the UK, particularly among younger people and men.
Sodium nitrite is commonly used for legitimate purposes, including food preservation. However, researchers say its accessibility, combined with the spread of harmful information online, may be contributing to an emerging suicide-prevention challenge.
Researchers examined postmortem testing data collected between March 2019 and August 2024. During that period, laboratories received 274 samples linked to 201 suspected deliberate or accidental poisoning cases across the UK, Ireland and Gibraltar.
For the main analysis, the researchers included 164 cases for which coroners had approved the use of the data. The number of cases submitted for nitrite and nitrate testing increased substantially after 2019.
The average age of people included in the analysis was approximately 28 years, with cases involving both teenagers and older adults. Nearly three-quarters of the cases involved younger people, while men accounted for substantially more cases than women, with 109 cases compared with 52.
Toxicological testing found unusually high levels of nitrite and nitrate in many of the cases. In 87 per cent of cases, concentrations were more than 100 times higher than normal physiological levels, which researchers said was consistent with intentional ingestion.
The findings have prompted concern because the people most frequently represented in the data were relatively young.
However, researchers cautioned that the study may capture only a fraction of deaths involving sodium nitrite because nitrite and nitrate testing is not routinely required in every suspected suicide or poisoning death. The time between death and laboratory testing also varied, potentially affecting the accuracy of biochemical measurements.
The authors said their analysis likely underestimates the actual number of sodium nitrite-related cases, adding that the study cannot establish how much the chemical has contributed to the overall suicide rate in the UK.
The researchers also identified the availability of information about sodium nitrite online as a major concern. They said information shared through online forums and other platforms could make dangerous methods easier for vulnerable people to discover.
They are therefore calling for greater efforts to restrict the spread of content that facilitates suicide, alongside measures aimed at controlling access to the chemical itself.
The research team said policymakers should consider tighter controls on sodium nitrite while ensuring that legitimate uses of the chemical are not unnecessarily disrupted.
They also recommended strengthening emergency responses to suspected poisoning and ensuring that appropriate antidote treatment is readily available to emergency medical teams, which could improve the chances of survival when poisoning is recognised quickly.
Professor Amrita Ahluwalia, the study’s lead researcher, said the findings were deeply concerning and underscored the need to reduce access to the chemical and limit the spread of harmful information online.
The researchers said the study highlights an emerging and potentially preventable source of deaths that may not be fully captured by existing surveillance systems.
They called for better testing, stronger safeguards around chemical access, responsible online information practices and rapid emergency treatment as part of a broader response.