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Hydroquinone																				Related Pages
Synonyms & Trade Names
			1,4-Benzenediol, p-Benzenediol, Dihydroxybenzene, 1,4-Dihydroxybenzene, Quinol
CAS No.
			123-31-9
	RTECS No.
			MX3500000
	DOT ID & Guide
			2662 153

FormulaC6H4(OH)2
	Conversion
	IDLH
			50 mg/m3See: 123319

Exposure Limits
			NIOSH RELC 2 mg/m3 [15-minute]
					OSHA PEL TWA 2 mg/m3
	Measurement Methods
			**NIOSH** 5004;**OSHA** PV2094
					
					See: NMAM or OSHA Methods
										
Physical Description
			Light-tan, light-gray, or colorless crystals.													
										
Molecular Weight110.1	
	Boiling Point545°F
	Melting Point338°F
	Solubility7%
	Vapor Pressure0.00001 mmHg
	Ionization Potential7.95 eV											
Specific Gravity1.33	
	Flash Point329°F (Molten)
	Upper Explosive Limit?
	Lower Explosive Limit?
Combustible Solid; dust cloud may explode if ignited in an enclosed area.
Incompatibilities & Reactivities
			Strong oxidizers, alkalis
Exposure Routes
			inhalation, ingestion, skin and/or eye contact
Symptoms
			irritation eyes: conjunctivitis; keratitis (inflammation of the cornea); central nervous system excitement; colored urine, nausea, dizziness, suffocation, rapid breath; muscle twitching, delirium; collapse; skin irritation, sensitization, dermatitis
Target Organs
			Eyes, skin, respiratory system, central nervous system
										
Personal Protection/Sanitation
			(See protection codes) **Skin:**Prevent skin contact
							**Eyes:**Prevent eye contact
							**Wash skin:**When contaminated
							**Remove:**When wet or contaminated
							**Change:**Daily
							**Provide:**Eyewash (>7%)
	First Aid
			(See procedures)**Eye:**Irrigate immediately
							**Skin:**Water flush
							**Breathing:**Respiratory support
							**Swallow:**Medical attention immediately
Respirator Recommendations
			**NIOSH/OSHA****Up to 50 mg/m3**: (APF = 25) Any powered, air-purifying respirator with a high-efficiency particulate filter.£/(APF = 50) Any air-purifying, full-facepiece respirator with an N100, R100, or P100 filter. Click here for information on selection of N, R, or P filters.(APF = 50) Any supplied-air respirator that has a tight-fitting facepiece and is 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 with an N100, R100, or P100 filter. Click here for information on selection of N, R, or P filters.Any appropriate escape-type, self-contained breathing apparatus
					Important additional information about respirator selection
See also
			INTRODUCTION
					  ICSC CARD: 0166
					  MEDICAL TESTS: 0120

			
							

			Page last reviewed:  October 30, 2019						Content
							source: 	National Institute for Occupational Safety and Health NIOSH Pocket Guide to Chemical Hazards
Introduction
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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
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