Nitrate toxicity is related primarily to the in vivo conversion to nitrite after ingestion [National Academy of Sciences (NAS) 1977; Swann 1975]. The health hazards from consuming water with nitrate are related to the direct toxicity of nitrite--that is, its ability to directly oxidize hemoglobin, changing it to methemoglobin, which cannot bind oxygen. Accumulation of methemoglobin (methemoglobinemia) occurs if this oxidation process overwhelms the protective reduction capacity of the cells (Jaffe 1981; Swann 1975). In addition to drinking water, which contributes an estimated in vivo formation of N-nitroso compounds from nitrite (Swann 1975). Nitrite is also a substrate in the formation of N-nitroso compounds from nitrosatable drugs. Therefore, higher dietary nitrate intake results in greater amounts being formed if there is concurrent exposure to nitrosatable drugs (Brender et al. 2004).