Potassium nitrate/nitrite, toxicity

DOT CLASSIFICATION 5.1 Label Oxidizer SAFETY PROFILE A powerftil oxidizer. Nitrites have been implicated as possible carcinogens. When heated to decomposition it emits toxic fumes of NOx, K2O, and Na20. See also POTASSIUM NITRATE and SODIUM NITRITE. 

Liquid metals are used when temperature requirement is so high that even the nitrate/nitrite salt mixture becomes unsuitable. The most commonly used liquid metal is a eutectic mixture of sodium and potassium (44%). This has a very broad temperature range (40-760°C) and very high thermal conductivity. Lead and lead-bismuth eutectic can be used up to 900° C. There are several disadvantages with the use of liquid metals. Special precautions must be taken while using alkali metals because they react violently with water and burn in air. Mercury, lead, and bismuth-based mixtures are highly toxic, hence their applications are restricted. One common use of liquid metals is in the cooling of nuclear reactors. 

MERCURIC THIOCYANATE (592-85-8) Hg(SCN)i Moderately unstable solid. Possible violent reaction with strong oxidizers strong acids organic peroxides, peroxides and hydroperoxides potassium chlorate potassium iodate, silver nitrate, sodium chlorate, nitric acid. Incompatible with ammonia, chlorates, hydrozoic acid, methyl isocyanoacetate, nitrates, nitrites, perchlorates, sodium peroxyborate, trinitrobenzoic acid, urea nitrate. When heated, this material swells to many times its original bulk. Attacks aluminum in the presence of moisture. Decomposes above 329°F/165°C, releasing toxic mercury and cyanide fumes, and sulfur and nitrogen oxides. On small fires, use dry chemical powder (such as Purple-K-Powder), alcohol-resistant foam, or COj extinguishers. MERCURIC (Spanish) (7439-97-6) see mercury. 

Nitrates are the salts involving the nitrate species (NO3 ), such as potassium nitrate. They are strong oxidizers and common components of explosives. Nitrate solutions may contain sufficient nitric acid to be corrosive. Nitrites involve the nitrite species (NO2 ) and include sodium nitrite, a characteristically strong oxidizer. Nitrites react with acids to evolve hydrogen cyanide and, as liquids, evolve toxic vapours. 

Sunlight and other sources of nonionizing electromagnetic radiation can affect foods. For example, it has been shown that sodium nitrite, sodium nitrate, sodium benzoate, potassium sorbate, and benzoic acid exhibit additive photogenotoxic effects on Escherichia coli, causing increased mutations upon exposure to sunlight. I76l Such effects potentially increase the toxic risks associated with food additives. 

BARIUM SULFIDE (21109-95-5) BaS Flammable solid. Oxidizes in dry air. Contact with acid, acid fumes, moisture, steam, or moist air causes decomposition with the formation of toxic and flammable hydrogen sulfide gas. Evolved gas can form explosive mixtures with air and may cause spontaneous ignition or explosion. Violent reaction with strong oxidizers, calcium chlorate calcium nitrate chlorine dioxide phosphorus(V) oxide strontium chlorate strontium nitrate. Incompatible with lead dioxide, potassium chlorate, potassium nitrite may explode at elevated temperatures. On small fires, use smothering quantities of dry chemical powder, dry clay, dry groimd limestone (CaCOj), dry soda ash,dry sand or approved Class D extinguishers, do not use water, foam, or hydrous agents. 

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