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Environmental Assessment

IRIS Toxicological Review of Hydrogen Cyanide and Cyanide Salts (Interagency Science Discussion Draft)

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Report Information

EPA is releasing the draft report, Toxicological Review of Hydrogen Cyanide (HCN) and Cyanide Salts, that was distributed to Federal agencies and White House Offices for comment during the Science Discussion step of the IRIS Assessment Development Process. Comments received from other Federal agencies and White House Offices are provided below with external peer review panel comments.

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Norman Birchfield
  • by phone at:   703-347-0174
  • by fax at:   703-347-8699
  • by email at:  birchfield.norman@epa.gov


The draft Toxicological Review of Hydrogen Cyanide and Cyanide Salts provides scientific support and rationale for the hazard and dose-response assessment pertaining to chronic exposure to hydrogen cyanide and cyanide salts. Cyanide compounds are used in a number of industrial processes including mining, electroplating, metallurgy, chemical manufacturing, and photography because these compounds can form stable complexes with a range of metals. Hydrogen cyanide is also a component of tobacco smoke, vehicle exhaust, and is produced by the burning of some plastics. Cyanide salts, such as potassium and sodium cyanide, are also used as rodenticides.


Jan 1987EPA posted an assessment for cyanide salts (RfD only).
Sep 1994EPA posted an assessment for hydrogen cyanide (RfC only).
Jun 2004The draft IRIS reassessment of hydrogen cyanide was started.
Sep 2009EPA released an external review draft of the assessment for public review and comment.
Oct 2009EPA announced a public listening session to be held on October 27, 2009. [Federal Register Notice Sep 23, 2009]
Nov 2009EPA announced an external peer review workshop to be held on December 14, 2009. [Federal Register Notice Nov 10, 2009]
Jan 2010EPA released the comments from the public comment period and external review workshop.
Aug 2010EPA hosted an interagency science discussion on the review of the draft document.
Sep 2010EPA released the final toxicological report and IRIS Summary for Hydrogen Cyanide and the interagency review draft with comments.

Next Steps

Now that the interagency review draft has been completed and finalized, this assessment has been loaded into the IRIS Web site and Database.


U.S. EPA. IRIS Toxicological Review of Hydrogen Cyanide and Cyanide Salts (Interagency Science Discussion Draft). U.S. Environmental Protection Agency, Washington, DC, EPA/635/R-08/016D, 2010.


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