Sodium nitrite
Inorganic compound used as food additive and cyanide antidote.
Sodium nitrite (NaNO₂) is an inorganic salt that appears as a white to slightly yellow crystalline powder. It dissolves easily in water and absorbs moisture from the air. Industrially, it is the most important nitrite salt, used to make pharmaceuticals, dyes, and pesticides, but it is most familiar as a food additive in processed meats and, in some countries, fish products.
In industrial chemistry, sodium nitrite is mainly used to produce organonitrogen compounds. It converts amines into diazo compounds, which are key building blocks for many dyes, including diazo dyes. It also helps make nitroso compounds used in the rubber industry. In metallurgy, it is used for phosphatizing and detinning. Sodium nitrite works as a corrosion inhibitor, added to industrial greases, used in aqueous solutions in closed-loop cooling systems, and even in molten form as a heat transfer medium.
As a food additive, sodium nitrite speeds up meat curing, stops *Clostridium botulinum* spores from germinating, and gives meat an appealing pink color. It reacts with myoglobin in meat, first turning it into bright red nitrosomyoglobin, then, when heated, into pink nitrosohemochrome. Historically, salt alone preserved meat, leaving it brownish-gray. Adding sodium nitrite with salt produces the red and pink colors associated with ham, bacon, hot dogs, and bologna. In the early 1900s, inconsistent curing led to research that standardized nitrite levels to balance effectiveness and safety. This research showed that sodium nitrite also improves taste, prevents lipid oxidation that causes rancidity, and extends storage life, though its ability to control harmful microorganisms varies. Meat industry scientists argue nitrite improves food safety, but this is disputed due to possible carcinogenic effects. Nitrite is labeled as E250 (potassium nitrite is E249) and is approved in the European Union, United States, Australia, and New Zealand. In processing, it is never used pure but mixed with common salt—called nitrited salt or curing salt. In Europe, this mix contains 99.1%–99.5% salt and 0.5%–0.9% nitrite; in the US, it is dosed at 6.25% nitrite and must be remixed with salt before use.
The red or pink color of cured meat is a key factor for consumer acceptance, and very little nitrite is needed—just 2 to 14 parts per million—to produce this color. Higher levels are required to keep the color
- chemical_formula
- NaNO2
- appearance
- White to slightly yellowish crystalline powder
- solubility
- Very soluble in water
- field
- Industrial chemistry, food science, medicine
- known_for
- Food additive in cured meats, treatment for cyanide poisoning, industrial precursor to dyes and pesticides
- e_number
- E250
Lore & Background
Sodium nitrite is primarily produced for industrial chemistry, where it is used to convert amines into diazo compounds, key precursors to many dyes. It also finds use in metallurgy for phosphatizing and detinning, and as a corrosion inhibitor in industrial greases and cooling systems. In food processing, it is mixed with common salt to create nitrited curing salt, which imparts a pink color to meats like ham and bacon and inhibits the germination of Clostridium botulinum spores. Its ability to delay lipid oxidation also extends the storage life of meat products.
As a medication, sodium nitrite is used together with sodium thiosulfate to treat severe cyanide poisoning, though it has largely been replaced by hydroxocobalamin. It works by creating methemoglobin, which binds cyanide more strongly than cytochrome C oxidase. Side effects include methemoglobinemia, low blood pressure, and headache. It came into medical use in the 1920s and 1930s and is on the World Health Organization's List of Essential Medicines.
In recent years, sodium nitrite has been associated with suicides, particularly after being ordered online. This led to lawsuits against Amazon, which were dismissed in June 2023, though a Washington Supreme Court ruling in February 2026 allowed families to pursue negligence claims. eBay globally prohibited its sale since 2019, and legislation was introduced in the United States in 2023 to ban products with more than 10% sodium nitrite concentration.
Reader's Guide
Sodium nitrite's significance spans multiple domains. Industrially, it is the most important nitrite salt, essential for producing dyes, pharmaceuticals, and pesticides. Its role as a food additive is controversial: while it improves meat color, taste, and safety by inhibiting botulism and rancidity, concerns about carcinogenic effects persist. The article notes that scientists working for the meat industry claim nitrite improves food safety, but this view is disputed. Medically, it remains a critical antidote for cyanide poisoning, though it has been largely superseded by hydroxocobalamin. Its legacy also includes a dark chapter as a suicide agent, prompting legal and regulatory actions. The compound illustrates the tension between industrial utility, public health benefits, and potential harms, with ongoing debates about its safety in food and its misuse in self-harm.
Did You Know?
- Sodium nitrite is used to treat cyanide poisoning by creating methemoglobin, which binds cyanide more strongly than cytochrome C oxidase.
- As little as 2 to 14 parts per million of sodium nitrite is needed to induce the desirable pink color in cured meat.
- Parma ham has been produced without nitrite since 1993 and was reported in 2018 to have caused no cases of botulism.
- eBay globally prohibited the sale of sodium nitrite since 2019.
More in Sodium Compounds 1-24
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