Hydroquinone

RTECS #

MX3500000

CAS #

123-31-9
See: NMAM or OSHA Methods

Updated

March 2019

Molecular Weight

110.12

Molecular Formula

C₆H₆O₂

Synonyms

1,4-Benzenediol
1,4-Dihydroxy-benzeen (Dutch)
1,4-Dihydroxybenzen (Czech)
1,4-Dihydroxybenzene
1,4-Dihydroxy-benzol (German)
1,4-Diidrobenzene (Italian)
alpha-Hydroquinone
Arctuvin
Benzene, p-dihydroxy-
Benzohydroquinone
Benzoquinol
beta-Quinol
Black and white bleaching cream
Dihydroxybenzene
Dihydroxybenzene (OSHA)
Eldopaque
Eldoquin
Hydrochinon (Czech, Polish)
Hydroquinol
Hydroquinole
Hydroquinone (ACGIH:OSHA)
Idrochinone (Italian)
NCI-C55834
p-Benzenediol
p-Dihydroxybenzene
p-Dioxobenzene
p-Dioxybenzene
Phiaquin
p-Hydroquinone
p-Hydroxyphenol
Pyrogentistic acid
Quinol
Tecquinol
Tenox HQ
Tequinol
USAF EK-356

Skin and Eye Irritation and References

Route/Organism	Dose	Effect	Reference
skin /human	2%	mild	ARDEAC 93,589,1966
skin /human	5%	severe	ARDEAC 93,589,1966
skin /human	3%		VCVGK* -,230,1994

Mutation Data and Reference

System Test	Route/Organism/Tissue	Dose	Reference
Cytogenetic Analysis	intraperitoneal/mouse	40 mg/kg	MUREAV 263,223,1991
Cytogenetic Analysis	ovary/hamster	20 mg/L	EMMUEG 10(Suppl 10),1,1987
Cytogenetic Analysis	embryo/hamster	30 µmol/L	MUREAV 373,113,1997
Cytogenetic Analysis	leukocyte/human	2 µmol/L/48H	CRNGDP 21,1485,2000
Cytogenetic Analysis	lymphocyte/human	50 µmol/L/48H	EMMUEG 45,388,2005
Cytogenetic Analysis	other cell types/human	20 µmol/L/48H	MUREAV 577S,1,2005
Cytogenetic Analysis	lymphocyte/human	20 µmol/L/48H	MUREAV 577S,1,2005
Cytogenetic Analysis	lung/hamster	80 µmol/L/2H (-enzymatic activation step)	MUTAEX 18,491,2003
Cytogenetic Analysis	lymphocyte/human	5 µmol/L/48H	EMS37* -,444,2006
Cytogenetic Analysis	lymphocyte/human	5 µmol/L	EMS37* -,444,2006
Cytogenetic Analysis	ovary/hamster	1 µmol/L/4H	MUREAV 661,57,2009
DNA adduct	bone marrow/human	500 µmol/L	CRNGDP 12,1181,1991
DNA Damage	lung/human	800 µmol/L	CBINA8 81,197,1992
DNA Damage	lymphocyte/human	100 µmol/L	EMMUEG 26,305,1995
DNA Damage	/Other microorganisms	1 mmol/L	MUREAV 368,235,1996
DNA Damage	liver/rat	400 µmol/L	CALEDQ 63,47,1992
DNA Damage	other cell types/mouse	2 µmol/L	MUREAV 715,25,2011
DNA Damage	other cell types/human	66 mg/kg/48H	MUREAV 649,54,2008
DNA Damage	other cell types/human	10 µmol/l/48H	MUREAV 696,21,2010
DNA Damage	liver/human	0.1 mmol/l/48H	MUREAV 696,21,2010
DNA Damage	liver/human	10 µmol/l/48H	MUREAV 696,21,2010
DNA Damage	ovary/hamster	0.5 µmol/L/3H	MUREAV 661,57,2009
DNA Damage	other cell types/human	100 µmol/L/24H (-enzymatic activation step)	MUREAV 760,23,2014
DNA Damage	other cell types/human	1 µmol/L/24H	MUREAV 760,23,2014
DNA Damage	other cell types/human	50 mg/L/18H	FCTOD7 55,557,2013
DNA Damage	other cell types/human	20 µmol/L/48H	MUREAV 577S,1,2005
DNA Damage	lymphocyte/human	20 µmol/L/48H	MUREAV 577S,1,2005
DNA Damage	ovary/hamster	2.5 mg/L/3H	MUREAV 537,151,2003
DNA inhibition	lymphocyte/mouse	10 µmol/L	MOPMA3 28,560,1985
DNA inhibition	lung/hamster	500 µmol/L	CRTOEC 4,151,1991
DNA inhibition	HeLa cell/human	100 µmol/L	MUREAV 92,427,1982
gene conversion and mitotic recombination	/Aspergillus nidulans	1 mmol/L	MUTAEX 2,235,1987
micronucleus test	intraperitoneal/mouse	20 mg/kg	MUREAV 341,29,1994
micronucleus test	subcutaneous/mouse	240 mg/kg/6D-continuous	CBINA8 39,129,1982
micronucleus test	lung/hamster	17500 nmol/L	EVHPAZ 82,81,1989
micronucleus test	lymphocyte/human	75 µmol/L	MUREAV 249,201,1991
micronucleus test	intraperitoneal/mouse	3 mg/kg/6D	TOLED5 121,15,2001
micronucleus test	lymphocyte/human	40 µmol/L/3H	EMMUEG 43,258,2004
micronucleus test	lung/hamster	5 µmol/L/12H	MUREAV 808,27,2016
micronucleus test	lung/hamster	10 µmol/L/3H	MUREAV 808,27,2016
micronucleus test	lung/hamster	10 µmol/L/6H	MUREAV 808,27,2016
micronucleus test	lung/hamster	5 µmol/L/18H	MUREAV 808,27,2016
micronucleus test	lung/hamster	10 µmol/L/24H	MUREAV 808,27,2016
micronucleus test	fibroblast/hamster	5 µmol/L/48H	MUREAV 770,37,2014
micronucleus test	ovary/hamster	10 µmol/L/4H	MUREAV 661,57,2009
micronucleus test	oral/mouse	80 mg/kg	MUREAV 208,61,1988
micronucleus test	other cell types/human	17.58 µmol/L/24H	EMMUEG 54,180,2013
micronucleus test	other cell types/human	2 mg/L/24H (-enzymatic activation step)	MUREAV 767,28,2014
micronucleus test	lymphocyte/human	2.5 mg/L/24H (-enzymatic activation step)	MUREAV 767,28,2014
morphological transform	fibroblast/mouse	10 µg/L/21D (-enzymatic activation step)	EMMUEG 37,231,2001
morphological transform	embryo/hamster	3 µmol/L	MUREAV 373,113,1997
mutation in mammalian somatic cells	lymphocyte/mouse	1250 µg/L	EMMUEG 11,91,1988
mutation in mammalian somatic cells	embryo/hamster	10 µmol/L	MUREAV 373,113,1997
mutation in microorganisms	lymphocyte/mouse	2500 µg/L (+enzymatic activation step)	EMMUEG 11,91,1988
mutation in microorganisms	/Salmonella typhimurium	2 µmol/plate (+enzymatic activation step)	MUREAV 90,91,1981
mutation in microorganisms	/Salmonella typhimurium	750 nmol/plate (-enzymatic activation step)	MUREAV 371,293,1996
mutation in microorganisms	/Escherichia coli	100 µg/plate (-enzymatic activation step)	MUREAV 467,41,2000
other mutation test systems	lymphocyte/human	5 µmol/L	CNREA8 45,2471,1985
other mutation test systems	oral/mouse	120 mg/kg	MUREAV 343,157,1995
other mutation test systems	lymphocyte/mouse	10 µmol/L	TOLED5 29,161,1985
other mutation test systems	other cell types/mouse	25 µmol/L	CBTOE2 2,231,1986
other mutation test systems	embryo/hamster	2 mg/L	MUREAV 287,47,1993
other mutation test systems	bone marrow/rabbit	6 µmol/L	CBINA8 50,203,1984
other mutation test systems	other cell types/human	35.44 µmol/L/24H	TIVIEQ 28,46,2014
sex chromosome loss and nondisjunction	embryo/hamster	1250 µg/L	MUREAV 287,47,1993
sex chromosome loss and nondisjunction	intraperitoneal/mouse	80 mg/kg	MUTAEX 4,208,1989
sex chromosome loss and nondisjunction	/Aspergillus nidulans	1 mmol/L	MUREAV 215,187,1989
sex chromosome loss and nondisjunction	lymphocyte/human	6 mg/L	MUREAV 287,57,1993
sex chromosome loss and nondisjunction	lymphocyte/human	75 µmol/L	MUREAV 322,9,1994
sex chromosome loss and nondisjunction	oral/Drosophila melanogaster	6 pph	MUREAV 469,215,2000
sister chromatid exchange	lymphocyte/human	5 µmol/L	CNREA8 45,2471,1985
sister chromatid exchange	embryo/hamster	1 µmol/L	MUREAV 373,113,1997
sister chromatid exchange	ovary/hamster	500 µg/L	EMMUEG 10(Suppl 10),1,1987
sister chromatid exchange	lung/hamster	20 µmol/L	EVHPAZ 82,81,1989
sister chromatid exchange	intravenous/mouse	600 mg/kg/3D	VCVGK* -,230,1994
sister chromatid exchange	lymphocyte/human	80 µmol/L/3H	EMMUEG 43,258,2004
specific locus test	lung/hamster	6 µmol/L/3D	FCTOD7 44,1940,2006
specific locus test	kidney/rat	25 µmol/L/4H	MOCAE8 31,37,2001
specific locus test	other cell types/human	10 µmol/L/24H	EMMUEG 54,737,2013
Unscheduled DNA Synthesis	embryo/hamster	1 µmol/L	MUREAV 373,113,1997
Unscheduled DNA Synthesis	oral/rat	8 gm/kg	JJIND8 74,1283,1985

Reproductive Effects Data and References

Route/Organism	Dose	Effect	Reference
oral/rat	2500 mg/kg (1-22D pregnant)	Reproductive: Effects on fertility: Post- implantation mortality (e.g., dead and/or resorbed implants per total number of implants)	AJANA2 110,29,1962
oral/rat	667 mg/kg (11D pregnant)	Reproductive: Effects on fertility: Post- implantation mortality (e.g., dead and/or resorbed implants per total number of implants)	TJADAB 41,43,1990
oral/rat	1 gm/kg (11D pregnant)	Reproductive: Effects on fertility: Litter size (e.g., # fetuses per litter; measured before birth)	TJADAB 41,43,1990
oral/rabbit	1950 mg/kg (6-18D pregnant)	Behavioral: Ataxia Reproductive: Specific developmental abnormalities: Craniofacial (including nose and tongue) Reproductive: Specific developmental abnormalities: Musculoskeletal system	NTIS** OTS0571419
subcutaneous/rat	5 mg/kg (1D prior to copulation)	Reproductive: Maternal effects: Ovaries, fallopian tubes	ENDOAO 57,466,1955
subcutaneous/rat	550 mg/kg (11D prior to copulation)	Reproductive: Maternal effects: Menstrual cycle changes or disorders	ENDOAO 57,466,1955
subcutaneous/rat	5100 mg/kg (51D male)	Reproductive: Paternal effects: Testes, epididymis, sperm duct Reproductive: Paternal effects: Prostate, seminal vesicle, Cowper's gland, accessory glands Reproductive: Effects on fertility: Male fertility index (e.g., # males impregnating females per # males exposed to fertile nonpregnant females)	SSZBAC 12,491,1965

Tumorigenic Data and References

Route/Organism	Dose	Effect	Reference
oral/mouse	toxic dose: 699 gm/kg/2Y- continuous	Tumorigenic: Neoplastic by RTECS criteria Liver: Tumors	JJCREP 82,1211,1991
oral/mouse	toxic dose: 26 gm/kg/2Y- intermittent	Tumorigenic: Carcinogenic by RTECS criteria Liver: Tumors	FCTOD7 30,737,1992
oral/mouse	lowest published toxic dose: 174720 mg/kg/26W- continuous	Tumorigenic: Carcinogenic by RTECS criteria Lung, Thorax, or Respiration: Tumors Liver: Tumors	CALEDQ 143,71,1999
oral/mouse	lowest published toxic dose: 174720 mg/kg/26W- continuous	Tumorigenic: Carcinogenic by RTECS criteria Tumorigenic: Facilitates action of known carcinogens Lung, Thorax, or Respiration: Tumors	CALEDQ 143,71,1999
oral/mouse	lowest published toxic dose: 25750 mg/kg/2Y- continuous	Tumorigenic: Neoplastic by RTECS criteria Liver: Tumors	NTPTR* NTP-TR-366,1989
oral/mouse	lowest published toxic dose: 25750 mg/kg/103W- intermittent	Tumorigenic: Neoplastic by RTECS criteria Liver: Tumors Endocrine: Thyroid weight (goiter)	NTIS** PB90-240389
oral/rat	lowest published toxic dose: 25750 mg/kg/2Y- continuous	Tumorigenic: Carcinogenic by RTECS criteria Kidney, Ureter, and Bladder: Kidney tumors	NTPTR* NTP-TR-366,1989
oral/rat	toxic dose: 256 gm/kg/2Y- continuous	Tumorigenic: Neoplastic by RTECS criteria Kidney, Ureter, and Bladder: Kidney tumors	EPASR* 8EHQ-0491-1210
oral/rat	toxic dose: 349 gm/kg/2Y- continuous	Tumorigenic: Neoplastic by RTECS criteria Kidney, Ureter, and Bladder: Kidney tumors	JJCREP 82,1211,1991
oral/rat	lowest published toxic dose: 12875 mg/kg/103W- intermittent	Tumorigenic: Neoplastic by RTECS criteria Kidney, Ureter, and Bladder: Kidney tumors	NTIS** PB90-240389
oral/rat	lowest published toxic dose: 12875 mg/kg/103W- intermittent	Tumorigenic: Carcinogenic by RTECS criteria Blood: Leukemia	NTIS** PB90-240389

Acute Toxicity Data and References

Route/Organism	Dose	Effect	Reference
In Vitro/Human, bone marrow	Inhibitor Concentration Low: 10 µmol/L/24H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc. In Vitro Toxicity Studies: Apoptosis in vitro	TOLED5 214,145,2012
In Vitro/Human, bone marrow	Inhibitor Concentration Low: 100 µmol/L/24H	In Vitro Toxicity Studies: Cell growth: Colony formation In Vitro Toxicity Studies: Cell viability (dye exclusion): trypan blue assay etc. In Vitro Toxicity Studies: Apoptosis in vitro	TIVIEQ 46,361,2018
In Vitro/Human, colon tumor	Inhibitor Concentration (50 percent kill): 70.88 µmol/L/24H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.	TIVIEQ 28,46,2014
In Vitro/Human, leukemia cells	Inhibitor Concentration Low: 20 µmol/L/48H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.	TOLED5 209,239,2012
In Vitro/Human, leukemia cells	Inhibitor Concentration Low: 0.08 mmol/L/24H	In Vitro Toxicity Studies: Cell viability (dye exclusion): trypan blue assay etc.	TOLED5 203,190,2011
In Vitro/Human, leukemia cells	Inhibitor Concentration Low: 0.04 mmol/L/24H	In Vitro Toxicity Studies: Other assays	TOLED5 203,190,2011
In Vitro/Human, leukemia cells	Inhibitor Concentration Low: 40 µmol/L/72H	In Vitro Toxicity Studies: Cell differentiation	TXCYAC 312,108,2013
In Vitro/Human, leukemia cells	Inhibitor Concentration (5 percent kill): 2.50 mg/L/30M	In Vitro Toxicity Studies: Cell counting	TIVIEQ 27,857,2013
In Vitro/Human, leukemia cells	Inhibitor Concentration Low: 0.60 mg/L/30M	In Vitro Toxicity Studies: Other assays	TIVIEQ 27,857,2013
In Vitro/Human, leukemia cells	Inhibitor Concentration Low: 2.5 µmol/L/48H	In Vitro Toxicity Studies: Other assays	TOLED5 259,133,2016
In Vitro/Human, leukemia cells	Inhibitor Concentration Low: 20 µmol/L/19W	Tumorigenic: Cells (cultured) transformed	TOLED5 259,133,2016
In Vitro/Human, leukemia cells	Inhibitor Concentration Low: 25 µmol/L/3D	In Vitro Toxicity Studies: Cell counting	TIVIEQ 40,1,2017
In Vitro/Human, leukemia cells	Inhibitor Concentration Low: 15 µmol/L/7D	In Vitro Toxicity Studies: Cell counting	TIVIEQ 40,1,2017
In Vitro/Human, leukemia cells	Inhibitor Concentration Low: 1 µmol/L/4W	In Vitro Toxicity Studies: Cell counting In Vitro Toxicity Studies: Apoptosis in vitro	TIVIEQ 40,1,2017
In Vitro/Human, leukemia cells	Inhibitor Concentration Low: 1 µmol/L/2W	In Vitro Toxicity Studies: Cell proliferation: DNA incorporation, mitotic index etc.	TIVIEQ 40,1,2017
In Vitro/Human, leukemia cells	Inhibitor Concentration (25 percent kill): 5.0 mg/L/24H	In Vitro Toxicity Studies: Cell viability (dye exclusion): trypan blue assay etc.	TIVIEQ 26,1150,2012
In Vitro/Human, leukemia cells	Inhibitor Concentration (50 percent kill): 2.13 mg/L/24H	In Vitro Toxicity Studies: Other assays	TIVIEQ 26,1150,2012
In Vitro/Human, liver	Inhibitor Concentration Low: 160 µmol/L/24H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.	TOLED5 214,209,2012
In Vitro/Human, liver	Inhibitor Concentration (50 percent kill): 300 µmol/L/24H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.	TOLED5 214,209,2012
In Vitro/Human, liver tumor	Inhibitor Concentration Low: 400 µmol/L/24H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.	FCTOD7 89,120,2016
In Vitro/Human, liver tumor	Inhibitor Concentration Low: 100 µmol/L/24H	In Vitro Toxicity Studies: Other assays	FCTOD7 89,120,2016
In Vitro/Human, liver tumor	Inhibitor Concentration (50 percent kill): 96 µmol/L	In Vitro Toxicity Studies: Other assays	TOLED5 196S,S154,2010
In Vitro/Human, liver tumor	Inhibitor Concentration Low: 250 µmol/L/48H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.	TIVIEQ 28,1507,2014
In Vitro/Human, liver tumor	Inhibitor Concentration Low: 250 µmol/L/24H	Biochemical: Metabolism (intermediary): Effect on mitochondrial function	TIVIEQ 28,1507,2014
In Vitro/Human, liver tumor	Inhibitor Concentration Low: 50 µmol/L/24H	In Vitro Toxicity Studies: Cell proliferation: DNA incorporation, mitotic index etc.	TIVIEQ 28,1507,2014
In Vitro/Human, liver tumor	Inhibitor Concentration Low: 10 µmol/L/48H	In Vitro Toxicity Studies: Other assays	TIVIEQ 28,1507,2014
In Vitro/Human, lung tumor	Inhibitor Concentration (20 percent kill): 337 µmol/L/1H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.	TIVIEQ 27,1072,2013
In Vitro/Human, lung tumor	Inhibitor Concentration (20 percent kill): 319 µmol/L/2H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.	TIVIEQ 27,1072,2013
In Vitro/Human, lung tumor	Inhibitor Concentration (20 percent kill): 220 µmol/L/4H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.	TIVIEQ 27,1072,2013
In Vitro/Human, lung tumor	Inhibitor Concentration (20 percent kill): 780 µmol/L/24H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.	TIVIEQ 27,1072,2013
In Vitro/Human, lung tumor	Inhibitor Concentration Low: 220 µmol/L/2H	In Vitro Toxicity Studies: Other assays	TIVIEQ 27,1072,2013
In Vitro/Human, lymphocyte	Inhibitor Concentration (30 percent kill): 6 mg/L/45H	In Vitro Toxicity Studies: Cell viability (dye exclusion): trypan blue assay etc.	TIVIEQ 29,901,2015
In Vitro/Human, lymphocyte	Inhibitor Concentration (50 percent kill): 1 mg/L/45H	In Vitro Toxicity Studies: Other assays	TIVIEQ 29,901,2015
In Vitro/Human, melanoma	Inhibitor Concentration Low: 25 mg/L/24H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.	TIVIEQ 32,339,2016
In Vitro/Human, melanoma	Inhibitor Concentration Low: 100 mg/L/24H	In Vitro Toxicity Studies: Apoptosis in vitro In Vitro Toxicity Studies: Cell morphology: overgrowth of cell appendixes etc.	TIVIEQ 32,339,2016
In Vitro/Human, melanoma	Inhibitor Concentration (50 percent kill): 87 µmol/L/48H	In Vitro Toxicity Studies: Other assays	JOETD7 149,570,2013
In Vitro/Human, melanoma	Inhibitor Concentration (50 percent kill): 45 µmol/L/48H	In Vitro Toxicity Studies: Cell membrane integrity: Cytoplasmic enzymes leakage (lactate dehydrogenase, ATP enzymes etc.)	JOETD7 149,570,2013
In Vitro/Human, monocyte	Inhibitor Concentration Low: 5 µmol/L/24H	Biochemical: Metabolism (intermediary): Effect on inflammation or mediation of inflammation	TXAPA9 256,35,2011
In Vitro/Human, monocyte	Inhibitor Concentration Low: 218 mg/L/2H	In Vitro Toxicity Studies: Other assays	TIVIEQ 27,1233,2013
In Vitro/Human, skin	Inhibitor Concentration Low: 5 mg/L/48H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.	TIVIEQ 32,339,2016
In Vitro/jda	Inhibitor Concentration Low: 25 µmol/L/24H	In Vitro Toxicity Studies: Cell viability (dye exclusion): trypan blue assay etc. In Vitro Toxicity Studies: Other assays	NRTXDN 39,102,2013
In Vitro/jda	Inhibitor Concentration Low: 100 µmol/L/24H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.	NRTXDN 39,102,2013
In Vitro/jda	Inhibitor Concentration Low: 50 µmol/L/24H	In Vitro Toxicity Studies: Cell membrane integrity: Cytoplasmic enzymes leakage (lactate dehydrogenase, ATP enzymes etc.)	NRTXDN 39,102,2013
In Vitro/jrd	Inhibitor Concentration (50 percent kill): 1.89 mg/L/24H	In Vitro Toxicity Studies: Other assays	TIVIEQ 28,626,2014
In Vitro/jti	Inhibitor Concentration Low: 15 µmol/L/20H	In Vitro Toxicity Studies: Cell differentiation In Vitro Toxicity Studies: Other assays	TXAPA9 244,273,2010
In Vitro/jzx	Inhibitor Concentration Low: 5 µmol/L/48H	In Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.	TOLED5 209,239,2012
In Vitro/jzx	Inhibitor Concentration Low: 2.5 µmol/L/48H	In Vitro Toxicity Studies: Other assays	TOLED5 209,239,2012
In Vitro/mtb	Inhibitor Concentration (50 percent kill): 11.01 µmol/L/6H	In Vitro Toxicity Studies: Other assays	TIVIEQ 32,287,2016
intraperitoneal/guinea pig	lowest published lethal dose: 200 mg/kg		VCVGK* -,229,1994
intraperitoneal/mouse	lethal dose (50 percent kill): 100 mg/kg		VCVGK* -,229,1994
intraperitoneal/rabbit	lethal dose (50 percent kill): 125 mg/kg		VCVGK* -,229,1994
intraperitoneal/rat	lethal dose (50 percent kill): 170 mg/kg		VCVGK* -,229,1994
intravenous/Dog	lowest published lethal dose: 80 mg/kg		VCVGK* -,229,1994
intravenous/rabbit	lowest published lethal dose: 100 mg/kg		AGSOA6 3,311,1962
intravenous/rat	lethal dose (50 percent kill): 115 mg/kg	Behavioral: Tremor Behavioral: Convulsions or effect on seizure threshold Behavioral: Excitement	FEPRA7 8,348,1949
intravenous/rat	lethal dose (50 percent kill): 115 mg/kg		VCVGK* -,229,1994
oral/cat	lethal dose (50 percent kill): 42 mg/kg	Behavioral: Ataxia Behavioral: Tetany Lung, Thorax, or Respiration: Dyspnea	VCVGK* -,229,1994
oral/cat	lethal dose (50 percent kill): 50 mg/kg		NTIS** OTS0555537
oral/Dog	lethal dose (50 percent kill): 200 mg/kg	Behavioral: Convulsions or effect on seizure threshold Behavioral: Excitement Gastrointestinal: Nausea or vomiting	FEPRA7 8,348,1949
oral/Dog	lethal dose (50 percent kill): 200 mg/kg	Behavioral: Ataxia Behavioral: Tetany Lung, Thorax, or Respiration: Dyspnea	VCVGK* -,229,1994
oral/guinea pig	lethal dose (50 percent kill): 550 mg/kg	Behavioral: Tremor Behavioral: Convulsions or effect on seizure threshold Behavioral: Excitement	FEPRA7 8,348,1949
oral/guinea pig	lethal dose (50 percent kill): 550 mg/kg	Behavioral: Ataxia Behavioral: Tetany Lung, Thorax, or Respiration: Dyspnea	VCVGK* -,229,1994
oral/human	lowest published lethal dose: 29 mg/kg		34ZIAG -,321,1969
oral/human	lowest published toxic dose: 170 mg/kg	Behavioral: Coma Cardiac: Pulse rate increased without fall in BP Lung, Thorax, or Respiration: Cyanosis	AMILAN 7,79,1927
oral/mammal (species unspecified)	lethal dose (50 percent kill): 480 mg/kg	Behavioral: Change in motor activity (specific assay) Behavioral: Muscle contraction or spasticity Lung, Thorax, or Respiration: Dyspnea	TPKVAL 15,136,1979
oral/mouse	lethal dose (50 percent kill): 245 mg/kg		GISAAA 38(8),6,1973
oral/mouse	lowest published toxic dose: 80 mg/kg/12H	Blood: Changes in bone marrow not included in above	MUREAV 208,61,1988
oral/mouse	lethal dose (50 percent kill): 350 mg/kg	Behavioral: Ataxia Behavioral: Tetany Lung, Thorax, or Respiration: Dyspnea	VCVGK* -,229,1994
oral/pigeon	lethal dose (50 percent kill): 300 mg/kg	Behavioral: Convulsions or effect on seizure threshold Behavioral: Excitement Gastrointestinal: Nausea or vomiting	FEPRA7 8,348,1949
oral/rabbit	lethal dose (50 percent kill): 200 mg/kg		IPSTB3 3,93,1976
oral/rabbit	lowest published lethal dose: 550 mg/kg	Behavioral: Ataxia Behavioral: Tetany Lung, Thorax, or Respiration: Dyspnea	VCVGK* -,229,1994
oral/rat	lowest published toxic dose: 200 mg/kg	Behavioral: Alteration of classical conditioning	FCTOD7 45,70,2007
oral/rat	lowest published toxic dose: 200 mg/kg	Behavioral: Change in motor activity (specific assay)	FCTOD7 45,70,2007
oral/rat	lowest published toxic dose: 96 mg/kg	Peripheral Nerve and Sensation: Recording from peripheral motor nerve Cardiac: Change in rate Vascular: BP lowering not characterized in autonomic section	TPKVAL 15,136,1979
oral/rat	lowest published toxic dose: 240 mg/kg	Behavioral: Tremor Behavioral: Change in motor activity (specific assay) Behavioral: Ataxia	TPKVAL 15,136,1979
oral/rat	lowest published lethal dose: 345 mg/kg	Behavioral: Tremor Behavioral: Convulsions or effect on seizure threshold Blood: Other changes	FCTOD7 45,70,2007
oral/rat	lowest published lethal dose: 285 mg/kg	Behavioral: Tremor Behavioral: Convulsions or effect on seizure threshold	FCTOD7 45,70,2007
oral/rat	lethal dose (50 percent kill): 320 mg/kg	Behavioral: Ataxia Behavioral: Tetany Lung, Thorax, or Respiration: Dyspnea	VCVGK* -,229,1994
oral/rat	lowest published toxic dose: 100 mg/kg	Behavioral: Tremor	FCTOD7 45,70,2007
oral/rat	lethal dose (50 percent kill): 367.3 mg/kg	Behavioral: Tremor Blood: Other changes	FCTOD7 45,70,2007
oral/rat	lethal dose (50 percent kill): 302 mg/kg		NTIS** OTS0555537
parenteral/frog	lowest published lethal dose: 190 mg/kg	Peripheral Nerve and Sensation: Spastic paralysis with/without sensory change Behavioral: Convulsions or effect on seizure threshold Cardiac: Other changes	AEPPAE 166,437,1932
skin/mammal (species unspecified)	lethal dose (50 percent kill): 5970 mg/kg		GISAAA 45(10),16,1980
skin/rabbit	lethal dose (50 percent kill): >2000 mg/kg/24H		FCTOD7 45,70,2007
subcutaneous/cat	lowest published lethal dose: 50 mg/kg		VCVGK* -,229,1994
subcutaneous/cat	lowest published lethal dose: 50 mg/kg	Behavioral: Tremor Vascular: Regional or general arteriolar or venous dilation Blood: Methemoglobinemia- Carboxhemoglobinemia	AEXPBL 72,241,1913
subcutaneous/Dog	lowest published lethal dose: 100 mg/kg		AEPPAE 183,319,1936
subcutaneous/frog	lowest published lethal dose: 190 mg/kg		HBTXAC 1,160,1955
subcutaneous/guinea pig	lowest published lethal dose: 300 mg/kg		VCVGK* -,229,1994
subcutaneous/mouse	lethal dose (50 percent kill): 182 mg/kg		ZGIMAL 2,333,1947
subcutaneous/rat	lowest published lethal dose: 300 mg/kg		VCVGK* -,229,1994
unreported route/mouse	lethal dose (50 percent kill): 150 mg/kg		BJCAAI 6,160,1952
unreported route/rat	lethal dose (50 percent kill): 720 mg/kg		GTPPAF 8,145,1972

Other Multiple Dose Data and References

Route/Organism	Dose	Effect	Reference
inhalation/mouse	lowest published toxic concentration: 12.5 ppm/1H/5D- intermittent	Biochemical: Metabolism (intermediary): Effect on inflammation or mediation of inflammation	TXCYAC 288,1,2011
inhalation/mouse	lowest published toxic concentration: 25 ppm/1H/5D- intermittent	Blood: Other changes Biochemical: Metabolism (intermediary): Effect on inflammation or mediation of inflammation	TXCYAC 288,1,2011
inhalation/mouse	lowest published toxic concentration: 125 ppm/5D- intermittent	Immunological Including Allergic: Decreased immune response Biochemical: Metabolism (intermediary): Effect on inflammation or mediation of inflammation	TXCYAC 296,20,2012
inhalation/mouse	lowest published toxic concentration: 0.04 ppm/1H/5D- intermittent	Lung, Thorax, or Respiration: Other changes Biochemical: Metabolism (intermediary): Effect on inflammation or mediation of inflammation	TOLED5 211,10,2012
inhalation/rat	lowest published toxic concentration: 10 mg/m³/4H/17W- intermittent	Blood: Normocytic anemia Blood: Changes in serum composition (e.g. TP, bilirubin, cholesterol) Blood: Changes in erythrocyte (RBC) count	GTPZAB 22(9),35,1978
intraperitoneal/mouse	lowest published toxic dose: 500 mg/kg/5D- intermittent	Biochemical: Enzyme inhibition, induction, or change in blood or tissue levels: Other oxidoreductases Skin and Appendages: Other: Hair	BPBLEO 30,2031,2007
intraperitoneal/rat	lowest published toxic dose: 650 mg/kg/17D- intermittent	Blood: Changes in bone marrow not included in above Blood: Changes in other cell count (unspecified) Blood: Changes in leukocyte (WBC) count	TXCYAC 220,126,2006
intraperitoneal/rat	lowest published toxic dose: 800 mg/kg/22D- intermittent	Lung, Thorax, or Respiration: Other changes Immunological Including Allergic: Increased immune response Biochemical: Metabolism (intermediary): Effect on inflammation or mediation of inflammation	TXCYAC 241,47,2007
intravenous/mouse	lowest published toxic dose: 600 mg/kg/3D- intermittent	Blood: Changes in spleen	VCVGK* -,230,1994
oral/cat	lowest published toxic dose: 220 mg/kg/14D- intermittent	Behavioral: Ataxia Nutritional and Gross Metabolic: Other changes Related to Chronic Data: Death in the "MULTIPLE DOSE" data type field	AEPPAE 183,319,1936
oral/cat	lowest published toxic dose: 1596 mg/kg/6W- continuous	Skin and Appendages: Other: Hair	VCVGK* -,230,1994
oral/mouse	lowest published toxic dose: 13 gm/kg/13W- intermittent	Liver: Changes in liver weight Related to Chronic Data: Death in the "MULTIPLE DOSE" data type field	NTPTR* NTP-TR-366,1989
oral/mouse	lowest published toxic dose: 32500 mg/kg/65W- intermittent	Brain and Coverings: Changes in brain weight Liver: Changes in liver weight Blood: Changes in cell count (unspecified)	NTPTR* NTP-TR-366,1989
oral/mouse	lowest published toxic dose: 3 gm/kg/14D- intermittent	Related to Chronic Data: Death in the "MULTIPLE DOSE" data type field	NTPTR* NTP-TR-366,1989
oral/rat	lowest published toxic dose: 1500 mg/kg/6W- intermittent	Kidney, Ureter, and Bladder: Changes in tubules (including acute renal failure, acute tubular necrosis) Biochemical: Enzyme inhibition, induction, or change in blood or tissue levels: Other enzymes	FAATDF 23,391,1994
oral/rat	lowest published toxic dose: 250 mg/kg/1W- intermittent	Biochemical: Enzyme inhibition, induction, or change in blood or tissue levels: Phosphatases	FAATDF 23,397,1994
oral/rat	lowest published toxic dose: 1500 mg/kg/6W- intermittent	Kidney, Ureter, and Bladder: Changes in tubules (including acute renal failure, acute tubular necrosis) Biochemical: Enzyme inhibition, induction, or change in blood or tissue levels: Multiple enzyme effects	FAATDF 23,397,1994
oral/rat	lowest published toxic dose: 1802500 mg/kg/103W- continuous	Nutritional and Gross Metabolic: Weight loss or decreased weight gain Related to Chronic Data: Death in the "MULTIPLE DOSE" data type field	PSEBAA -,684,1953
oral/rat	lowest published toxic dose: 18200 mg/kg/26W- continuous	Nutritional and Gross Metabolic: Weight loss or decreased weight gain	VCVGK* -,230,1994
oral/rat	lowest published toxic dose: 236 gm/kg/9W- continuous	Gastrointestinal: Ulceration or bleeding from stomach Blood: Changes in bone marrow not included in above Nutritional and Gross Metabolic: Weight loss or decreased weight gain	PSEBAA 84,684,1953
oral/rat	lowest published toxic dose: 13 gm/kg/13W- intermittent	Liver: Changes in liver weight Related to Chronic Data: Death in the "MULTIPLE DOSE" data type field	NTPTR* NTP-TR-366,1989
oral/rat	lowest published toxic dose: 6 gm/kg/14D- intermittent	Related to Chronic Data: Death in the "MULTIPLE DOSE" data type field	NTPTR* NTP-TR-366,1989
oral/rat	lowest published toxic dose: 640 mg/kg/2W- intermittent	Behavioral: Tremor	FCTOD7 45,70,2007
oral/rat	lowest published toxic dose: 1920 mg/kg/6W- intermittent	Behavioral: Tremor	FCTOD7 45,70,2007
oral/rat	lowest published toxic dose: 4000 mg/kg/4W- intermittent	Behavioral: Somnolence (general depressed activity) Behavioral: Change in motor activity (specific assay)	FCTOD7 45,70,2007
oral/rat	lowest published toxic dose: 1000 mg/kg/1W- intermittent	Behavioral: Somnolence (general depressed activity) Behavioral: Change in motor activity (specific assay)	FCTOD7 45,70,2007
oral/rat	lowest published toxic dose: 2275 mg/kg/13W- continuous	Liver: Other changes	FCTOD7 45,1620,2007
oral/rat	lowest published toxic dose: 2800 mg/kg/14D- intermittent	Blood: Changes in leukocyte (WBC) count	JOETD7 215,83,2018
skin/mouse	lowest published toxic dose: 150 mg/kg/3D- intermittent	Skin: After topical application: Cutaneous sensitization (experimental) Biochemical: Metabolism (intermediary): Effect on inflammation or mediation of inflammation	TXCYAC 212,69,2005

Reviews

Organization	Standard	Reference
American Conference of Governmental Industrial Hygienists (ACGIH)	Threshold Limit Value-time-weighted average 1 mg/m³ (sen)	DTLVS* TLV/BEI,2013
American Conference of Governmental Industrial Hygienists (ACGIH)	Threshold Limit Value-Confirmed animal carcinogen	DTLVS* TLV/BEI,2013
International Agency for Research on Cancer (IARC)	Cancer Review:Animal Limited Evidence	IMEMDT 71,691,1999
International Agency for Research on Cancer (IARC)	Cancer Review:Animal Inadequate Evidence	IMEMDT 15,155,1977
International Agency for Research on Cancer (IARC)	Cancer Review:Human No Adequate Data	IMEMDT 15,155,1977
International Agency for Research on Cancer (IARC)	Cancer Review:Human Inadequate Evidence	IMEMDT 71,691,1999
International Agency for Research on Cancer (IARC)	Cancer Review:Group 3	IMEMDT 71,691,1999
TOXICOLOGY REVIEW		AEHLAU 23,6,1971
TOXICOLOGY REVIEW		MUREAV 47,75,1978
TOXICOLOGY REVIEW		MUREAV 566,99,2004
TOXICOLOGY REVIEW		MUREAV 488,151,2001
TOXICOLOGY REVIEW		TOLED5 140-141,53,2003
TOXICOLOGY REVIEW		MUREAV 543,201,2003
TOXICOLOGY REVIEW		EMMUEG 43,143,2004
TOXICOLOGY REVIEW		MUREAV 627,10,2007
TOXICOLOGY REVIEW		ENTOX* -,555,2005
TOXICOLOGY REVIEW		MUREAV 584,1,2005
TOXICOLOGY REVIEW		BCLPT* 96,131,2005
TOXICOLOGY REVIEW		MUREAV 658,215,2008
TOXICOLOGY REVIEW		DERCL* 25,233,2007
TOXICOLOGY REVIEW		MUTAEX 23,271,2008
TOXICOLOGY REVIEW		TXAPA9 243,239,2010
TOXICOLOGY REVIEW		MUTAEX 24,383,2009
TOXICOLOGY REVIEW		MUTAEX 26,223,2011
TOXICOLOGY REVIEW		MUREAV 653,99,2008
TOXICOLOGY REVIEW		MUREAV 721,27,2011
TOXICOLOGY REVIEW		MUREAV 751,49,2012
TOXICOLOGY REVIEW		MUREAV 751,247,2012
TOXICOLOGY REVIEW		TXAPA9 250,87,2011
TOXICOLOGY REVIEW		MUREAV 783,66,2015
TOXICOLOGY REVIEW		MUREAV 764,31,2015
TOXICOLOGY REVIEW		MUREAV 786-788,14,2015
TOXICOLOGY REVIEW		EMMUEG 55,679,2014
TOXICOLOGY REVIEW		MUREAV 795,7,2016
TOXICOLOGY REVIEW		MUREAV 802,1,2016
TOXICOLOGY REVIEW		FCTOD7 94,93,2016
TOXICOLOGY REVIEW		PYTOEY 21,1534,2014
TOXICOLOGY REVIEW		MUREAV 770,170,2016
TOXICOLOGY REVIEW		MUTAEX 31,347,2016
TOXICOLOGY REVIEW		RTOPDW 55,43,2009
TOXICOLOGY REVIEW		RTOPDW 61,1,2011

Standards and Regulations

Organization	Standard	Reference
Mine Safety and Health Administration (MSHA) STANDARD-air	time-weighted average 2 mg/m³	DTLVS* 3,133,1971
Occupational Exposure Limit IN ARGENTINA, BULGARIA, COLOMBIA, JORDAN check ACGIH TLV;
Occupational Exposure Limit IN SINGAPORE, VIETNAM check ACGIH TLV
Occupational Exposure Limit-AUSTRALIA	time-weighted average 2 mg/m³, JUL2008
Occupational Exposure Limit-AUSTRIA	MAK-TMW 2 mg/m³;KZW 4 mg/m³, inhal, sen, 2007
Occupational Exposure Limit-BELGIUM	time-weighted average 2 mg/m³, MAR2002
Occupational Exposure Limit-DENMARK	ceiling concentration 2 mg/m³, carc, MAY2011
Occupational Exposure Limit-FINLAND	time-weighted average 0.5 mg/m³, short term exposure limit 2 mg/m³, NOV2011
Occupational Exposure Limit-FRANCE	VME 2 mg/m³, FEB2006
Occupational Exposure Limit-ICELAND	time-weighted average 0.5 mg/m³, short term exposure limit 2 mg/m³, sen, NOV2011
Occupational Exposure Limit-JAPAN	s2 sen, MAY2012
Occupational Exposure Limit-KOREA	time-weighted average 2 mg/m³, 2006
Occupational Exposure Limit-MEXICO	time-weighted average 2 mg/m³, 2004
Occupational Exposure Limit-NEW ZEALAND	time-weighted average 2 mg/m³, JAN2002
Occupational Exposure Limit-PERU	time-weighted average 2 mg/m³, JUL2005
Occupational Exposure Limit-POLAND	MAC(time-weighted average) 2 mg/m³, MAC(short term exposure limit) 4 mg/m³, JAN1999
Occupational Exposure Limit-RUSSIA	short term exposure limit 1 mg/m³, Skin, JUN2003
Occupational Exposure Limit-SWEDEN	time-weighted average 0.5 mg/m³;short term exposure limit 1.5 mg/m³, Sen, JUN2005
Occupational Exposure Limit-SWITZERLAND	ceiling concentration 2 mg/m³, carc 3, inhal, skin, sen, JAN2011
Occupational Exposure Limit-THE NETHERLANDS	MAC-TGG 2 mg/m³, 2003
Occupational Exposure Limit-THE PHILIPPINES	time-weighted average 2 mg/m³, JAN1993
Occupational Exposure Limit-TURKEY	time-weighted average 2 mg/m³, JAN1993
Occupational Exposure Limit-UNITED KINGDOM	time-weighted average 0.5 mg/m³, OCT2007
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Construction)	8H time-weighted average 2 mg/m³	CFRGBR 29,1926.55,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Federal Contractors)	8H time-weighted average 2 mg/m³	CFRGBR 41,50-204.50,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (General Industry)	8H time-weighted average 2 mg/m³	CFRGBR 29,1910.1000,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Shipyards)	8H time-weighted average 2 mg/m³	CFRGBR 29,1915.1000,1993

NIOSH Documentation and Surveillance

Organization	Standard	Reference
National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Level TO HYDROQUINONE-air	ceiling concentration 2 mg/m³/15M	NIOSH* DHHS #92-100,1992
National Occupational Exposure Survey 1983	Hazard Code M0747; Number of Industries 177; Total Number of Facilities 40917; Number of Occupations 136; Total Number of Employees Exposed 442749; Total Number of Female Employees Exposed 144063
National Occupational Hazard Survey 1974	Hazard Code M0747; Number of Industries 143; Total Number of Facilities 24380; Number of Occupations 88; Total Number of Employees Exposed 116192

Status in Federal Agencies

Organization	Reference
EPA TSCA 8(a) PRELIMINARY ASSESSMENT INFORMATION, FINAL RULE	FEREAC 47,26992,82
EPA TSCA Section 8(b) CHEMICAL INVENTORY
EPA TSCA Section 8(d) unpublished health/safety studies
EPA TSCA TEST SUBMISSION (TSCATS) DATA BASE, JANUARY 2001
NCI Carcinogenesis Studies (gavage);equivocal evidence:mouse,rat
NIOSH Analytical Method, 1994: Hydroquinone, 5004
NTP Carcinogenesis Studies (gavage);some evidence:mouse,rat NTPTR* NTP-TR-366,1989
On EPA IRIS database

Page last reviewed: November 16, 2018

Content source: National Institute for Occupational Safety and Health