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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/OrganismDoseEffectReference
skin /human 2% mildARDEAC 93,589,1966
skin /human 5% severeARDEAC 93,589,1966
skin /human 3%VCVGK* -,230,1994

Mutation Data and Reference

System TestRoute/Organism/TissueDoseReference
Cytogenetic Analysisintraperitoneal/mouse40 mg/kgMUREAV 263,223,1991
Cytogenetic Analysisovary/hamster20 mg/LEMMUEG 10(Suppl 10),1,1987
Cytogenetic Analysisembryo/hamster30 µmol/LMUREAV 373,113,1997
Cytogenetic Analysisleukocyte/human2 µmol/L/48HCRNGDP 21,1485,2000
Cytogenetic Analysislymphocyte/human50 µmol/L/48HEMMUEG 45,388,2005
Cytogenetic Analysisother cell types/human20 µmol/L/48HMUREAV 577S,1,2005
Cytogenetic Analysislymphocyte/human20 µmol/L/48HMUREAV 577S,1,2005
Cytogenetic Analysislung/hamster80 µmol/L/2H (-enzymatic activation step)MUTAEX 18,491,2003
Cytogenetic Analysislymphocyte/human5 µmol/L/48HEMS37* -,444,2006
Cytogenetic Analysislymphocyte/human5 µmol/LEMS37* -,444,2006
Cytogenetic Analysisovary/hamster1 µmol/L/4HMUREAV 661,57,2009
DNA adductbone marrow/human500 µmol/LCRNGDP 12,1181,1991
DNA Damagelung/human800 µmol/LCBINA8 81,197,1992
DNA Damagelymphocyte/human100 µmol/LEMMUEG 26,305,1995
DNA Damage/Other microorganisms1 mmol/LMUREAV 368,235,1996
DNA Damageliver/rat400 µmol/LCALEDQ 63,47,1992
DNA Damageother cell types/mouse2 µmol/LMUREAV 715,25,2011
DNA Damageother cell types/human66 mg/kg/48HMUREAV 649,54,2008
DNA Damageother cell types/human10 µmol/l/48HMUREAV 696,21,2010
DNA Damageliver/human0.1 mmol/l/48HMUREAV 696,21,2010
DNA Damageliver/human10 µmol/l/48HMUREAV 696,21,2010
DNA Damageovary/hamster0.5 µmol/L/3HMUREAV 661,57,2009
DNA Damageother cell types/human100 µmol/L/24H (-enzymatic activation step)MUREAV 760,23,2014
DNA Damageother cell types/human1 µmol/L/24HMUREAV 760,23,2014
DNA Damageother cell types/human50 mg/L/18HFCTOD7 55,557,2013
DNA Damageother cell types/human20 µmol/L/48HMUREAV 577S,1,2005
DNA Damagelymphocyte/human20 µmol/L/48HMUREAV 577S,1,2005
DNA Damageovary/hamster2.5 mg/L/3HMUREAV 537,151,2003
DNA inhibitionlymphocyte/mouse10 µmol/LMOPMA3 28,560,1985
DNA inhibitionlung/hamster500 µmol/LCRTOEC 4,151,1991
DNA inhibitionHeLa cell/human100 µmol/LMUREAV 92,427,1982
gene conversion and mitotic recombination/Aspergillus nidulans1 mmol/LMUTAEX 2,235,1987
micronucleus testintraperitoneal/mouse20 mg/kgMUREAV 341,29,1994
micronucleus testsubcutaneous/mouse240 mg/kg/6D-continuousCBINA8 39,129,1982
micronucleus testlung/hamster17500 nmol/LEVHPAZ 82,81,1989
micronucleus testlymphocyte/human75 µmol/LMUREAV 249,201,1991
micronucleus testintraperitoneal/mouse3 mg/kg/6DTOLED5 121,15,2001
micronucleus testlymphocyte/human40 µmol/L/3HEMMUEG 43,258,2004
micronucleus testlung/hamster5 µmol/L/12HMUREAV 808,27,2016
micronucleus testlung/hamster10 µmol/L/3HMUREAV 808,27,2016
micronucleus testlung/hamster10 µmol/L/6HMUREAV 808,27,2016
micronucleus testlung/hamster5 µmol/L/18HMUREAV 808,27,2016
micronucleus testlung/hamster10 µmol/L/24HMUREAV 808,27,2016
micronucleus testfibroblast/hamster5 µmol/L/48HMUREAV 770,37,2014
micronucleus testovary/hamster10 µmol/L/4HMUREAV 661,57,2009
micronucleus testoral/mouse80 mg/kgMUREAV 208,61,1988
micronucleus testother cell types/human17.58 µmol/L/24HEMMUEG 54,180,2013
micronucleus testother cell types/human2 mg/L/24H (-enzymatic activation step)MUREAV 767,28,2014
micronucleus testlymphocyte/human2.5 mg/L/24H (-enzymatic activation step)MUREAV 767,28,2014
morphological transformfibroblast/mouse10 µg/L/21D (-enzymatic activation step)EMMUEG 37,231,2001
morphological transformembryo/hamster3 µmol/LMUREAV 373,113,1997
mutation in mammalian somatic cellslymphocyte/mouse1250 µg/LEMMUEG 11,91,1988
mutation in mammalian somatic cellsembryo/hamster10 µmol/LMUREAV 373,113,1997
mutation in microorganismslymphocyte/mouse2500 µg/L (+enzymatic activation step)EMMUEG 11,91,1988
mutation in microorganisms/Salmonella typhimurium2 µmol/plate (+enzymatic activation step)MUREAV 90,91,1981
mutation in microorganisms/Salmonella typhimurium750 nmol/plate (-enzymatic activation step)MUREAV 371,293,1996
mutation in microorganisms/Escherichia coli100 µg/plate (-enzymatic activation step)MUREAV 467,41,2000
other mutation test systemslymphocyte/human5 µmol/LCNREA8 45,2471,1985
other mutation test systemsoral/mouse120 mg/kgMUREAV 343,157,1995
other mutation test systemslymphocyte/mouse10 µmol/LTOLED5 29,161,1985
other mutation test systemsother cell types/mouse25 µmol/LCBTOE2 2,231,1986
other mutation test systemsembryo/hamster2 mg/LMUREAV 287,47,1993
other mutation test systemsbone marrow/rabbit6 µmol/LCBINA8 50,203,1984
other mutation test systemsother cell types/human35.44 µmol/L/24HTIVIEQ 28,46,2014
sex chromosome loss and nondisjunctionembryo/hamster1250 µg/LMUREAV 287,47,1993
sex chromosome loss and nondisjunctionintraperitoneal/mouse80 mg/kgMUTAEX 4,208,1989
sex chromosome loss and nondisjunction/Aspergillus nidulans1 mmol/LMUREAV 215,187,1989
sex chromosome loss and nondisjunctionlymphocyte/human6 mg/LMUREAV 287,57,1993
sex chromosome loss and nondisjunctionlymphocyte/human75 µmol/LMUREAV 322,9,1994
sex chromosome loss and nondisjunctionoral/Drosophila melanogaster6 pphMUREAV 469,215,2000
sister chromatid exchangelymphocyte/human5 µmol/LCNREA8 45,2471,1985
sister chromatid exchangeembryo/hamster1 µmol/LMUREAV 373,113,1997
sister chromatid exchangeovary/hamster500 µg/LEMMUEG 10(Suppl 10),1,1987
sister chromatid exchangelung/hamster20 µmol/LEVHPAZ 82,81,1989
sister chromatid exchangeintravenous/mouse600 mg/kg/3DVCVGK* -,230,1994
sister chromatid exchangelymphocyte/human80 µmol/L/3HEMMUEG 43,258,2004
specific locus testlung/hamster6 µmol/L/3DFCTOD7 44,1940,2006
specific locus testkidney/rat25 µmol/L/4HMOCAE8 31,37,2001
specific locus testother cell types/human10 µmol/L/24HEMMUEG 54,737,2013
Unscheduled DNA Synthesisembryo/hamster1 µmol/LMUREAV 373,113,1997
Unscheduled DNA Synthesisoral/rat8 gm/kgJJIND8 74,1283,1985

Reproductive Effects Data and References

Route/OrganismDoseEffectReference
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 tubesENDOAO 57,466,1955
subcutaneous/rat 550 mg/kg (11D prior to copulation)Reproductive: Maternal effects: Menstrual cycle changes or disordersENDOAO 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/OrganismDoseEffectReference
oral/mouse toxic dose: 699 gm/kg/2Y- continuousTumorigenic: Neoplastic by RTECS criteria

Liver: Tumors
JJCREP 82,1211,1991
oral/mouse toxic dose: 26 gm/kg/2Y- intermittentTumorigenic: Carcinogenic by RTECS criteria

Liver: Tumors
FCTOD7 30,737,1992
oral/mouse lowest published toxic dose: 174720 mg/kg/26W- continuousTumorigenic: 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- continuousTumorigenic: 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- continuousTumorigenic: Neoplastic by RTECS criteria

Liver: Tumors
NTPTR* NTP-TR-366,1989
oral/mouse lowest published toxic dose: 25750 mg/kg/103W- intermittentTumorigenic: Neoplastic by RTECS criteria

Liver: Tumors

Endocrine: Thyroid weight (goiter)
NTIS** PB90-240389
oral/rat lowest published toxic dose: 25750 mg/kg/2Y- continuousTumorigenic: Carcinogenic by RTECS criteria

Kidney, Ureter, and Bladder: Kidney tumors
NTPTR* NTP-TR-366,1989
oral/rat toxic dose: 256 gm/kg/2Y- continuousTumorigenic: Neoplastic by RTECS criteria

Kidney, Ureter, and Bladder: Kidney tumors
EPASR* 8EHQ-0491-1210
oral/rat toxic dose: 349 gm/kg/2Y- continuousTumorigenic: Neoplastic by RTECS criteria

Kidney, Ureter, and Bladder: Kidney tumors
JJCREP 82,1211,1991
oral/rat lowest published toxic dose: 12875 mg/kg/103W- intermittentTumorigenic: Neoplastic by RTECS criteria

Kidney, Ureter, and Bladder: Kidney tumors
NTIS** PB90-240389
oral/rat lowest published toxic dose: 12875 mg/kg/103W- intermittentTumorigenic: Carcinogenic by RTECS criteria

Blood: Leukemia
NTIS** PB90-240389

Acute Toxicity Data and References

Route/OrganismDoseEffectReference
In Vitro/Human, bone marrow Inhibitor Concentration Low: 10 µmol/L/24HIn 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/24HIn 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/24HIn 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/48HIn 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/24HIn 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/24HIn Vitro Toxicity Studies: Other assaysTOLED5 203,190,2011
In Vitro/Human, leukemia cells Inhibitor Concentration Low: 40 µmol/L/72HIn Vitro Toxicity Studies: Cell differentiationTXCYAC 312,108,2013
In Vitro/Human, leukemia cells Inhibitor Concentration (5 percent kill): 2.50 mg/L/30MIn Vitro Toxicity Studies: Cell countingTIVIEQ 27,857,2013
In Vitro/Human, leukemia cells Inhibitor Concentration Low: 0.60 mg/L/30MIn Vitro Toxicity Studies: Other assaysTIVIEQ 27,857,2013
In Vitro/Human, leukemia cells Inhibitor Concentration Low: 2.5 µmol/L/48HIn Vitro Toxicity Studies: Other assaysTOLED5 259,133,2016
In Vitro/Human, leukemia cells Inhibitor Concentration Low: 20 µmol/L/19WTumorigenic: Cells (cultured) transformedTOLED5 259,133,2016
In Vitro/Human, leukemia cells Inhibitor Concentration Low: 25 µmol/L/3DIn Vitro Toxicity Studies: Cell countingTIVIEQ 40,1,2017
In Vitro/Human, leukemia cells Inhibitor Concentration Low: 15 µmol/L/7DIn Vitro Toxicity Studies: Cell countingTIVIEQ 40,1,2017
In Vitro/Human, leukemia cells Inhibitor Concentration Low: 1 µmol/L/4WIn 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/2WIn 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/24HIn 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/24HIn Vitro Toxicity Studies: Other assaysTIVIEQ 26,1150,2012
In Vitro/Human, liver Inhibitor Concentration Low: 160 µmol/L/24HIn 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/24HIn 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/24HIn 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/24HIn Vitro Toxicity Studies: Other assaysFCTOD7 89,120,2016
In Vitro/Human, liver tumor Inhibitor Concentration (50 percent kill): 96 µmol/LIn Vitro Toxicity Studies: Other assaysTOLED5 196S,S154,2010
In Vitro/Human, liver tumor Inhibitor Concentration Low: 250 µmol/L/48HIn 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/24HBiochemical: Metabolism (intermediary): Effect on mitochondrial functionTIVIEQ 28,1507,2014
In Vitro/Human, liver tumor Inhibitor Concentration Low: 50 µmol/L/24HIn 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/48HIn Vitro Toxicity Studies: Other assaysTIVIEQ 28,1507,2014
In Vitro/Human, lung tumor Inhibitor Concentration (20 percent kill): 337 µmol/L/1HIn 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/2HIn 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/4HIn 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/24HIn 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/2HIn Vitro Toxicity Studies: Other assaysTIVIEQ 27,1072,2013
In Vitro/Human, lymphocyte Inhibitor Concentration (30 percent kill): 6 mg/L/45HIn 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/45HIn Vitro Toxicity Studies: Other assaysTIVIEQ 29,901,2015
In Vitro/Human, melanoma Inhibitor Concentration Low: 25 mg/L/24HIn 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/24HIn 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/48HIn Vitro Toxicity Studies: Other assaysJOETD7 149,570,2013
In Vitro/Human, melanoma Inhibitor Concentration (50 percent kill): 45 µmol/L/48HIn 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/24HBiochemical: Metabolism (intermediary): Effect on inflammation or mediation of inflammationTXAPA9 256,35,2011
In Vitro/Human, monocyte Inhibitor Concentration Low: 218 mg/L/2HIn Vitro Toxicity Studies: Other assaysTIVIEQ 27,1233,2013
In Vitro/Human, skin Inhibitor Concentration Low: 5 mg/L/48HIn Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.TIVIEQ 32,339,2016
In Vitro/jdaInhibitor Concentration Low: 25 µmol/L/24HIn Vitro Toxicity Studies: Cell viability (dye exclusion): trypan blue assay etc.

In Vitro Toxicity Studies: Other assays
NRTXDN 39,102,2013
In Vitro/jdaInhibitor Concentration Low: 100 µmol/L/24HIn Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.NRTXDN 39,102,2013
In Vitro/jdaInhibitor Concentration Low: 50 µmol/L/24HIn Vitro Toxicity Studies: Cell membrane integrity: Cytoplasmic enzymes leakage (lactate dehydrogenase, ATP enzymes etc.)NRTXDN 39,102,2013
In Vitro/jrdInhibitor Concentration (50 percent kill): 1.89 mg/L/24HIn Vitro Toxicity Studies: Other assaysTIVIEQ 28,626,2014
In Vitro/jtiInhibitor Concentration Low: 15 µmol/L/20HIn Vitro Toxicity Studies: Cell differentiation

In Vitro Toxicity Studies: Other assays
TXAPA9 244,273,2010
In Vitro/jzxInhibitor Concentration Low: 5 µmol/L/48HIn Vitro Toxicity Studies: Cell viability (mitochondrial reductase assays): MTT, XTT, MTS, WSTs assays etc.TOLED5 209,239,2012
In Vitro/jzxInhibitor Concentration Low: 2.5 µmol/L/48HIn Vitro Toxicity Studies: Other assaysTOLED5 209,239,2012
In Vitro/mtbInhibitor Concentration (50 percent kill): 11.01 µmol/L/6HIn Vitro Toxicity Studies: Other assaysTIVIEQ 32,287,2016
intraperitoneal/guinea pig lowest published lethal dose: 200 mg/kgVCVGK* -,229,1994
intraperitoneal/mouse lethal dose (50 percent kill): 100 mg/kgVCVGK* -,229,1994
intraperitoneal/rabbit lethal dose (50 percent kill): 125 mg/kgVCVGK* -,229,1994
intraperitoneal/rat lethal dose (50 percent kill): 170 mg/kgVCVGK* -,229,1994
intravenous/Dog lowest published lethal dose: 80 mg/kgVCVGK* -,229,1994
intravenous/rabbit lowest published lethal dose: 100 mg/kgAGSOA6 3,311,1962
intravenous/rat lethal dose (50 percent kill): 115 mg/kgBehavioral: Tremor

Behavioral: Convulsions or effect on seizure threshold

Behavioral: Excitement
FEPRA7 8,348,1949
intravenous/rat lethal dose (50 percent kill): 115 mg/kgVCVGK* -,229,1994
oral/cat lethal dose (50 percent kill): 42 mg/kgBehavioral: Ataxia

Behavioral: Tetany

Lung, Thorax, or Respiration: Dyspnea
VCVGK* -,229,1994
oral/cat lethal dose (50 percent kill): 50 mg/kgNTIS** OTS0555537
oral/Dog lethal dose (50 percent kill): 200 mg/kgBehavioral: 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/kgBehavioral: Ataxia

Behavioral: Tetany

Lung, Thorax, or Respiration: Dyspnea
VCVGK* -,229,1994
oral/guinea pig lethal dose (50 percent kill): 550 mg/kgBehavioral: Tremor

Behavioral: Convulsions or effect on seizure threshold

Behavioral: Excitement
FEPRA7 8,348,1949
oral/guinea pig lethal dose (50 percent kill): 550 mg/kgBehavioral: Ataxia

Behavioral: Tetany

Lung, Thorax, or Respiration: Dyspnea
VCVGK* -,229,1994
oral/human lowest published lethal dose: 29 mg/kg34ZIAG -,321,1969
oral/human lowest published toxic dose: 170 mg/kgBehavioral: 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/kgBehavioral: 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/kgGISAAA 38(8),6,1973
oral/mouse lowest published toxic dose: 80 mg/kg/12HBlood: Changes in bone marrow not included in aboveMUREAV 208,61,1988
oral/mouse lethal dose (50 percent kill): 350 mg/kgBehavioral: Ataxia

Behavioral: Tetany

Lung, Thorax, or Respiration: Dyspnea
VCVGK* -,229,1994
oral/pigeon lethal dose (50 percent kill): 300 mg/kgBehavioral: 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/kgIPSTB3 3,93,1976
oral/rabbit lowest published lethal dose: 550 mg/kgBehavioral: Ataxia

Behavioral: Tetany

Lung, Thorax, or Respiration: Dyspnea
VCVGK* -,229,1994
oral/rat lowest published toxic dose: 200 mg/kgBehavioral: Alteration of classical conditioningFCTOD7 45,70,2007
oral/rat lowest published toxic dose: 200 mg/kgBehavioral: Change in motor activity (specific assay)FCTOD7 45,70,2007
oral/rat lowest published toxic dose: 96 mg/kgPeripheral 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/kgBehavioral: Tremor

Behavioral: Change in motor activity (specific assay)

Behavioral: Ataxia
TPKVAL 15,136,1979
oral/rat lowest published lethal dose: 345 mg/kgBehavioral: Tremor

Behavioral: Convulsions or effect on seizure threshold

Blood: Other changes
FCTOD7 45,70,2007
oral/rat lowest published lethal dose: 285 mg/kgBehavioral: Tremor

Behavioral: Convulsions or effect on seizure threshold
FCTOD7 45,70,2007
oral/rat lethal dose (50 percent kill): 320 mg/kgBehavioral: Ataxia

Behavioral: Tetany

Lung, Thorax, or Respiration: Dyspnea
VCVGK* -,229,1994
oral/rat lowest published toxic dose: 100 mg/kgBehavioral: TremorFCTOD7 45,70,2007
oral/rat lethal dose (50 percent kill): 367.3 mg/kgBehavioral: Tremor

Blood: Other changes
FCTOD7 45,70,2007
oral/rat lethal dose (50 percent kill): 302 mg/kgNTIS** OTS0555537
parenteral/frog lowest published lethal dose: 190 mg/kgPeripheral 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/kgGISAAA 45(10),16,1980
skin/rabbit lethal dose (50 percent kill): >2000 mg/kg/24HFCTOD7 45,70,2007
subcutaneous/cat lowest published lethal dose: 50 mg/kgVCVGK* -,229,1994
subcutaneous/cat lowest published lethal dose: 50 mg/kgBehavioral: Tremor

Vascular: Regional or general arteriolar or venous dilation

Blood: Methemoglobinemia- Carboxhemoglobinemia
AEXPBL 72,241,1913
subcutaneous/Dog lowest published lethal dose: 100 mg/kgAEPPAE 183,319,1936
subcutaneous/frog lowest published lethal dose: 190 mg/kgHBTXAC 1,160,1955
subcutaneous/guinea pig lowest published lethal dose: 300 mg/kgVCVGK* -,229,1994
subcutaneous/mouse lethal dose (50 percent kill): 182 mg/kgZGIMAL 2,333,1947
subcutaneous/rat lowest published lethal dose: 300 mg/kgVCVGK* -,229,1994
unreported route/mouse lethal dose (50 percent kill): 150 mg/kgBJCAAI 6,160,1952
unreported route/rat lethal dose (50 percent kill): 720 mg/kgGTPPAF 8,145,1972

Other Multiple Dose Data and References

Route/OrganismDoseEffectReference
inhalation/mouse lowest published toxic concentration: 12.5 ppm/1H/5D- intermittentBiochemical: Metabolism (intermediary): Effect on inflammation or mediation of inflammationTXCYAC 288,1,2011
inhalation/mouse lowest published toxic concentration: 25 ppm/1H/5D- intermittentBlood: 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- intermittentImmunological 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- intermittentLung, 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- intermittentBlood: 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- intermittentBiochemical: 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- intermittentBlood: 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- intermittentLung, 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- intermittentBlood: Changes in spleenVCVGK* -,230,1994
oral/cat lowest published toxic dose: 220 mg/kg/14D- intermittentBehavioral: 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- continuousSkin and Appendages: Other: HairVCVGK* -,230,1994
oral/mouse lowest published toxic dose: 13 gm/kg/13W- intermittentLiver: 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- intermittentBrain 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- intermittentRelated to Chronic Data: Death in the "MULTIPLE DOSE" data type fieldNTPTR* NTP-TR-366,1989
oral/rat lowest published toxic dose: 1500 mg/kg/6W- intermittentKidney, 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- intermittentBiochemical: Enzyme inhibition, induction, or change in blood or tissue levels: PhosphatasesFAATDF 23,397,1994
oral/rat lowest published toxic dose: 1500 mg/kg/6W- intermittentKidney, 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- continuousNutritional 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- continuousNutritional and Gross Metabolic: Weight loss or decreased weight gainVCVGK* -,230,1994
oral/rat lowest published toxic dose: 236 gm/kg/9W- continuousGastrointestinal: 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- intermittentLiver: 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- intermittentRelated to Chronic Data: Death in the "MULTIPLE DOSE" data type fieldNTPTR* NTP-TR-366,1989
oral/rat lowest published toxic dose: 640 mg/kg/2W- intermittentBehavioral: TremorFCTOD7 45,70,2007
oral/rat lowest published toxic dose: 1920 mg/kg/6W- intermittentBehavioral: TremorFCTOD7 45,70,2007
oral/rat lowest published toxic dose: 4000 mg/kg/4W- intermittentBehavioral: 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- intermittentBehavioral: 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- continuousLiver: Other changesFCTOD7 45,1620,2007
oral/rat lowest published toxic dose: 2800 mg/kg/14D- intermittentBlood: Changes in leukocyte (WBC) countJOETD7 215,83,2018
skin/mouse lowest published toxic dose: 150 mg/kg/3D- intermittentSkin: After topical application: Cutaneous sensitization (experimental)

Biochemical: Metabolism (intermediary): Effect on inflammation or mediation of inflammation
TXCYAC 212,69,2005

Reviews

OrganizationStandardReference
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 carcinogenDTLVS* TLV/BEI,2013
International Agency for Research on Cancer (IARC)Cancer Review:Animal Limited EvidenceIMEMDT 71,691,1999
International Agency for Research on Cancer (IARC)Cancer Review:Animal Inadequate EvidenceIMEMDT 15,155,1977
International Agency for Research on Cancer (IARC)Cancer Review:Human No Adequate DataIMEMDT 15,155,1977
International Agency for Research on Cancer (IARC)Cancer Review:Human Inadequate EvidenceIMEMDT 71,691,1999
International Agency for Research on Cancer (IARC)Cancer Review:Group 3IMEMDT 71,691,1999
TOXICOLOGY REVIEWAEHLAU 23,6,1971
TOXICOLOGY REVIEWMUREAV 47,75,1978
TOXICOLOGY REVIEWMUREAV 566,99,2004
TOXICOLOGY REVIEWMUREAV 488,151,2001
TOXICOLOGY REVIEWTOLED5 140-141,53,2003
TOXICOLOGY REVIEWMUREAV 543,201,2003
TOXICOLOGY REVIEWEMMUEG 43,143,2004
TOXICOLOGY REVIEWMUREAV 627,10,2007
TOXICOLOGY REVIEWENTOX* -,555,2005
TOXICOLOGY REVIEWMUREAV 584,1,2005
TOXICOLOGY REVIEWBCLPT* 96,131,2005
TOXICOLOGY REVIEWMUREAV 658,215,2008
TOXICOLOGY REVIEWDERCL* 25,233,2007
TOXICOLOGY REVIEWMUTAEX 23,271,2008
TOXICOLOGY REVIEWTXAPA9 243,239,2010
TOXICOLOGY REVIEWMUTAEX 24,383,2009
TOXICOLOGY REVIEWMUTAEX 26,223,2011
TOXICOLOGY REVIEWMUREAV 653,99,2008
TOXICOLOGY REVIEWMUREAV 721,27,2011
TOXICOLOGY REVIEWMUREAV 751,49,2012
TOXICOLOGY REVIEWMUREAV 751,247,2012
TOXICOLOGY REVIEWTXAPA9 250,87,2011
TOXICOLOGY REVIEWMUREAV 783,66,2015
TOXICOLOGY REVIEWMUREAV 764,31,2015
TOXICOLOGY REVIEWMUREAV 786-788,14,2015
TOXICOLOGY REVIEWEMMUEG 55,679,2014
TOXICOLOGY REVIEWMUREAV 795,7,2016
TOXICOLOGY REVIEWMUREAV 802,1,2016
TOXICOLOGY REVIEWFCTOD7 94,93,2016
TOXICOLOGY REVIEWPYTOEY 21,1534,2014
TOXICOLOGY REVIEWMUREAV 770,170,2016
TOXICOLOGY REVIEWMUTAEX 31,347,2016
TOXICOLOGY REVIEWRTOPDW 55,43,2009
TOXICOLOGY REVIEWRTOPDW 61,1,2011

Standards and Regulations

OrganizationStandardReference
Mine Safety and Health Administration (MSHA) STANDARD-airtime-weighted average 2 mg/m3DTLVS* 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-AUSTRALIAtime-weighted average 2 mg/m3, JUL2008
Occupational Exposure Limit-AUSTRIAMAK-TMW 2 mg/m3;KZW 4 mg/m3, inhal, sen, 2007
Occupational Exposure Limit-BELGIUMtime-weighted average 2 mg/m3, MAR2002
Occupational Exposure Limit-DENMARKceiling concentration 2 mg/m3, carc, MAY2011
Occupational Exposure Limit-FINLANDtime-weighted average 0.5 mg/m3, short term exposure limit 2 mg/m3, NOV2011
Occupational Exposure Limit-FRANCEVME 2 mg/m3, FEB2006
Occupational Exposure Limit-ICELANDtime-weighted average 0.5 mg/m3, short term exposure limit 2 mg/m3, sen, NOV2011
Occupational Exposure Limit-JAPANs2 sen, MAY2012
Occupational Exposure Limit-KOREAtime-weighted average 2 mg/m3, 2006
Occupational Exposure Limit-MEXICOtime-weighted average 2 mg/m3, 2004
Occupational Exposure Limit-NEW ZEALANDtime-weighted average 2 mg/m3, JAN2002
Occupational Exposure Limit-PERUtime-weighted average 2 mg/m3, JUL2005
Occupational Exposure Limit-POLANDMAC(time-weighted average) 2 mg/m3, MAC(short term exposure limit) 4 mg/m3, JAN1999
Occupational Exposure Limit-RUSSIAshort term exposure limit 1 mg/m3, Skin, JUN2003
Occupational Exposure Limit-SWEDENtime-weighted average 0.5 mg/m3;short term exposure limit 1.5 mg/m3, Sen, JUN2005
Occupational Exposure Limit-SWITZERLANDceiling concentration 2 mg/m3, carc 3, inhal, skin, sen, JAN2011
Occupational Exposure Limit-THE NETHERLANDSMAC-TGG 2 mg/m3, 2003
Occupational Exposure Limit-THE PHILIPPINEStime-weighted average 2 mg/m3, JAN1993
Occupational Exposure Limit-TURKEYtime-weighted average 2 mg/m3, JAN1993
Occupational Exposure Limit-UNITED KINGDOMtime-weighted average 0.5 mg/m3, OCT2007
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Construction)8H time-weighted average 2 mg/m3CFRGBR 29,1926.55,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Federal Contractors)8H time-weighted average 2 mg/m3CFRGBR 41,50-204.50,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (General Industry)8H time-weighted average 2 mg/m3CFRGBR 29,1910.1000,1994
Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (Shipyards)8H time-weighted average 2 mg/m3CFRGBR 29,1915.1000,1993

NIOSH Documentation and Surveillance

OrganizationStandardReference
National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Level TO HYDROQUINONE-airceiling concentration 2 mg/m3/15MNIOSH* DHHS #92-100,1992
National Occupational Exposure Survey 1983Hazard 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 1974Hazard 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

OrganizationReference
EPA TSCA 8(a) PRELIMINARY ASSESSMENT INFORMATION, FINAL RULEFEREAC 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