CASRN 14797-55-8 | DTXSID5024217

Protocol for the Nitrate and Nitrite IRIS Assessment (Oral) (Preliminary Assessment Materials)

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In November 2023, EPA released the Protocol for the Nitrate and Nitrite IRIS Assessment (Oral) (Preliminary Assessment Materials) for a 30-day public review and comment period. As part of developing a draft IRIS assessment, EPA presents a protocol that describes the methodology for how the assessment will be conducted, including systematic review and dose-response. These could include strategies for literature searches, criteria for study inclusion or exclusion, considerations for evaluating study methods, information management for extracting data, approaches for synthesis within and across lines of evidence, and methods for derivation of toxicity values.


U.S. EPA. Protocol for the Nitrate and Nitrite IRIS Assessment (Oral) (Preliminary Assessment Materials). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-23/337, 2023.

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Nitrate (NO3−) and nitrite (NO2−), naturally occurring anions in the environment, play an essential role in Earth’s nitrogen cycle. Since 1950, human sources of nitrogen have increased substantially, creating a global surplus of nitrate/nitrite that supersedes natural sources by about 30%. Nitrate salts are mainly used as nitrogen fertilizers and in industrial explosives, fireworks, and glass making, whereas nitrites are largely used as preservatives for meat and fish curing and as color fixatives.


Date Description
01- Sep 2017 EPA released the IRIS Assessment Plan (IAP) for Nitrate and Nitrite for public comment and review. [Federal Register Notice Sep 18, 2017]
02- Sep 2017 EPA's Science Advisory Board (SAB) Chemical Assessment Advisory Committee (CAAC) hosted a public meeting on September 27-28, 2017 to discuss the assessment. Information regarding the meeting can be found on the SAB website.
03- Apr 2019 EPA suspended the assessment in fiscal year 2019. It may be restarted as Agency priorities change.
04- Jun 2023 The assessment was unsuspended and announced in the June 2023 Outlook.
05- Nov 2023 EPA released the Protocol for the Nitrates and Nitrites IRIS Assessment (Preliminary Assessment Materials). The deadline for comments is December 11, 2023. [Federal Register Notice Nov 9, 2023]


The IRIS Program will use the protocol to develop the draft assessment.

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This download(s) is distributed solely for the purpose of pre-dissemination peer review under applicable information quality guidelines. It has not been formally disseminated by EPA. It does not represent and should not be construed to represent any Agency determination or policy.

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Federal Register Notices


Comments on the assessment may be submitted and reviewed using the Docket ID EPA-HQ-ORD-2017-0496

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