Skip directly to site content Skip directly to page options Skip directly to A-Z link


Centers for Disease Control and Prevention. CDC twenty four seven. Saving Lives, Protecting People
					Search
		×
			NIOSH
			NIOSH
				All CDC
				Submit
			For a full list of topics:A-Z Index
			Advanced Search
		Advanced Search


The National Institute for Occupational Safety and Health (NIOSH)


Facebook
        Twitter
        LinkedIn
        Syndicate





Hydrogen cyanide																				Related Pages
Synonyms & Trade Names
			Formonitrile, Hydrocyanic acid, Prussic acid
CAS No.
			74-90-8
	RTECS No.
			MW6825000
	DOT ID & Guide
			1051 117(>20% solution)1051 117(anhydrous)1613 154(< or =20% solution)

FormulaHCN
	Conversion
			1 ppm = 1.10 mg/m3
	IDLH
			50 ppmSee: 74908

Exposure Limits
			NIOSH RELST 4.7 ppm (5 mg/m3) [skin]
					OSHA PEL TWA 10 ppm (11 mg/m3) [skin] See Appendix G
	Measurement Methods
			**NIOSH** 6010 , 6017
					
					See: NMAM or OSHA Methods
										
Physical Description
			Colorless or pale-blue liquid or gas (above 78°F) with a bitter, almond-like odor.
					[Note: Often used as a 96% solution in water.]													
										
Molecular Weight27.0	
	Boiling Point78°F (96%)
	Freezing Point7°F (96%)
	SolubilityMiscible
	Vapor Pressure630 mmHg
	Ionization Potential13.60 eV											
Specific Gravity0.69	
	Flash Point0°F (96%)
	Upper Explosive Limit40.0%
	Lower Explosive Limit5.6%
Class IA Flammable Liquid: Fl.P. below 73°F and BP below 100°F. Flammable Gas
Incompatibilities & Reactivities
			Amines, oxidizers, acids, sodium hydroxide, calcium hydroxide, sodium carbonate, caustics, ammonia
					[Note: Can polymerize at 122-140°F.]
Exposure Routes
			inhalation, skin absorption, ingestion, skin and/or eye contact
Symptoms
			asphyxia; lassitude (weakness, exhaustion), headache, confusion; nausea, vomiting; increased rate and depth of respiration or respiration slow and gasping; thyroid, blood changes
Target Organs
			central nervous system, cardiovascular system, thyroid, blood
										
Personal Protection/Sanitation
			(See protection codes) **Skin:**Prevent skin contact
							**Eyes:**Prevent eye contact
							**Wash skin:**When contaminated
							**Remove:**When wet (flammable)
							**Change:**No recommendation
							**Provide:**Eyewash, Quick drench
	First Aid
			(See procedures)**Eye:**Irrigate immediately
							**Skin:**Water flush immediately
							**Breathing:**Respiratory support
							**Swallow:**Medical attention immediately
Respirator Recommendations
			**NIOSH****Up to 47 ppm**: (APF = 10) Any supplied-air respirator**Up to 50 ppm**: (APF = 25) Any supplied-air respirator operated in a continuous-flow mode(APF = 50) Any self-contained breathing apparatus with a full facepiece(APF = 50) Any supplied-air respirator with a full facepiece**Emergency or planned entry into unknown concentrations or IDLH conditions:** (APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus**Escape:** (APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted canister providing protection against the compound of concernAny appropriate escape-type, self-contained breathing apparatus
				Important additional information about respirator selection
See also
			INTRODUCTION
					  ICSC CARD: 0492
					  MEDICAL TESTS: 0117

			
							

			Page last reviewed:  October 30, 2019						Content
							source: 	National Institute for Occupational Safety and Health NIOSH Pocket Guide to Chemical Hazards
Introduction
Search the Pocket Guide
Chemical Names, Synonyms and Trade Names
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
CAS Numbers
RTECS Numbers
Appendices
A – NIOSH Potential Occupational Carcinogens
B – Thirteen OSHA-Regulated Carcinogens
C – Supplementary Exposure Limits
D – Substances with No Established RELs
E – OSHA Respirator Requirements for Selected Chemicals
F – Miscellaneous Notes
G – 1989 Air Contaminants Update Project: Exposure Limits NOT in Effect
Type C & CE – Definitions for Type C and Type CE Respirators
Personal Protection and Sanitation Codes
First Aid Procedures Follow NIOSH Facebook
Pinterest
Twitter
YouTube
 NIOSH Homepage NIOSH A-Z
Workplace Safety & Health Topics
Publications and Products
Programs
Contact NIOSH


About CDC
					Contact Us
					800-232-4636
 Facebook Twitter Instagram LinkedIn Youtube Pinterest Snapchat
 CONTACT CDC
				Contact Us
							Call 800-232-4636
							Email Us
			ABOUT CDC
				About CDC
							Jobs
							Funding
			POLICIES
				Accessibility
							External Links
							Privacy
							Policies
							No Fear Act
							FOIA
							OIG
							Nondiscrimination
							Vulnerability Disclosure Policy
			CONNECT WITH US
				Facebook
								Twitter
								Instagram
								LinkedIn
							Youtube
								Pinterest
								Snapchat
								Email
			LANGUAGES
				Español
							繁體中文
							Tiếng Việt
							한국어
							Tagalog
							Русский
							العربية
							Kreyòl Ayisyen
							Français
							Polski
							Português
							Italiano
							Deutsch
							日本語
							فارسی
							English


U.S. Department of Health & Human Services
			Accessibility
			External Links
			Privacy
			Policies
			No Fear Act
			FOIA
			Nondiscrimination
			OIG
			Vulnerability Disclosure Policy
			USA.gov


Exit Notification/Disclaimer Policy Close
 Links with this icon  indicate that you are leaving the CDC website. The Centers for Disease Control and Prevention (CDC) cannot attest to the accuracy of a non-federal website.
					Linking to a non-federal website does not constitute an endorsement by CDC or any of its employees of the sponsors or the information and products presented on the website.
					You will be subject to the destination website's privacy policy when you follow the link.
					CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website. Website Disclaimers
 Cancel Continue