Hydrocarbons, C6, isoalkanes, <5% n-hexane

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Migrated Data from field(s)
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Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

Due to migration, the value was transferred to one of the current document's attachments

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study is classified as reliable without restrictions because it is well documented and follows OECD Guideline 471.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

The method was modified to use the dessicator methodology in order to test the mutagenicity of the vapor phase of the test substance.

GLP compliance:

yes (incl. QA statement)

Type of assay:

bacterial reverse mutation assay

Species / strain / cell type:

S. typhimurium, other: TA 1535, TA 1537, TA 1538, TA 98, TA 100

Metabolic activation:

with and without

Metabolic activation system:

S9 from aroclor induced rat liver

Test concentrations with justification for top dose:

Migrated Data from field(s)
Field "Justification for deviation from the high dose level" (Path: ENDPOINT_STUDY_RECORD.GeneticToxicityVitro.MaterialsAndMethods.Method.JustificationForDeviationFromTheHighDoseLevel): 0, 600, 1000, 3000, 6000, 9000 ppm

Untreated negative controls:

yes

Negative solvent / vehicle controls:

other: no solvent used

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: 2-aminoanthracene, 2-nitrofluorene, sodium azide, 9-aminoacridine, 1,1-dichloroethene

Details on test system and experimental conditions:

METHOD OF APPLICATION: Prepared plates were placed uncovered and inverted in 9l dessicators. An appropriate amount of test substance was placed in a glass petri dish was suspended at the bottom of the dessicator. A magnetic stirring bar was placed at the bottom of the dessicator, and served as a fan to ensure even distribution of the vapor.


DURATION
- Preincubation period: 48 hrs
- Exposure duration: 7-8 hrs at 37 degree C
- Expression time (cells in growth medium): There was an additional incubation time of 40 hrs after exposure.

NUMBER OF REPLICATIONS: 3

Evaluation criteria:

To be considered positive for mutation, at least a doubling of mean revertants per plate in at least one tester strain must be seen. This increase must be dose-related.

Statistics:

Mean number of revertant per plate and the standard deviation was calculated.

Key result

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not examined

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not examined

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 1538

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not examined

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not examined

Untreated negative controls validity:

valid

Positive controls validity:

valid

Key result

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

not examined

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

No positive responses were observed in any of the tester strains. The positive control substance, 2-aminoanthracene, did not produce any mutations in strain TA 1538 in one experiment in the presence of S9. As revertants were seen in the test of TA 1538 without S9, and revertants were seen in other strains exposed to positive controls with S9, the lack of revertants was most likely due to a technical error and the study is still considered valid.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Average Revertants per Plate (SD) - Experiment B1

Dose (ppm)	TA 98	TA 100	TA 1535	TA 1537	TA 1538
Without S9
0.0	17 ± 1	105 ± 12	11 ± 1	7 ± 1	8
600	20 ± 5	113 ±  9	13 ± 4	6 ± 1	6
1000	16 ± 3	121 ± 8	14 ± 2	7 ± 1	6
3000	18 ± 4	112 ± 13	17 ± 3	5 ± 4	4
6000	24 ± 4	117 ± 14	12 ± 4	6 ± 4	8
9000	17 ± 3	112 ± 7	14 ± 5	9 ± 2	5
Positive control	227 ± 8	422 ± 44	349 ± 36	481 ± 135	452
With S9
0.0	24 ± 5	119 ± 10	17 ± 1	7 ± 0	12
600	30 ± 10	137 ± 12	23 ± 4	9 ± 4	15
1000	23 ± 5	126 ± 3	14 ± 2	11 ± 5	13
3000	22 ± 1	120 ± 19	16 ± 2	9 ± 2	9
6000	24 ± 2	103 ± 11	14 ± 4	7 ± 2	11
9000	30 ± 6	120 ± 3	17 ± 1	8 ± 2	14
Positive control	3142 ± 139	3902 ± 68	189±  22	351 ± 26	--
Positive vapor control		372 ± 52

Average Revertants per Plate (SD) - Experiment B2

Dose (ppm)	TA 98	TA 100	TA 1535	TA 1537	TA 1538
Without S9
0.0	12 ± 2	107 ± 11	9 ± 5	5 ± 1	19
600	20 ± 1	103 ±  9	8 ± 4	7 ± 3	19
1000	14 ± 4	110 ± 6	12 ± 5	7 ± 2	19
3000	14 ± 1	124 ± 14	12 ± 2	7 ± 2	19
6000	22 ± 6	125 ± 14	15 ± 1	5 ± 2	16
9000	15 ± 6	114 ± 5	13 ± 3	5 ± 3	13
Positive control	444 ± 86	991 ± 67	758 ± 19	162 ± 51	754
With S9
0.0	21 ± 4	132 ± 16	17 ± 4	7 ± 3	26
600	25 ± 7	133 ± 8	18 ± 2	6 ± 1	25
1000	22 ± 2	155 ± 4	15 ± 7	8 ± 3	25
3000	20 ± 1	123 ± 23	16 ± 7	7 ± 3	24
6000	21 ± 4	151 ± 14	15 ± 1	6 ± 2	30
9000	25 ± 4	161 ± 8	11 ± 4	6 ± 1	27
Positive control	2187 ± 166	2229 ± 223	166 ±  32	230 ± 24	2195
Positive vapor control		394 ± 50

Conclusions:

Interpretation of results: negative

The test substance is not mutagenic.

Executive summary:

This study examined the mutagenicity of vapors of the test substance commercial hexane. Plates of S. typhimurium were exposed for 7 -8 hrs to test atmospheres of 0, 600, 1000, 3000, 6000, or 9000 ppm of test substance. 20,000 ppm of 1,1 -dichloroethene was used a vapor-phase positive control substance. The test substance did not produce a positive response in any of the test strains. The test substance is not mutagenic.

Reference 2

Endpoint:

in vitro gene mutation study in mammalian cells

Remarks:

Type of genotoxicity: gene mutation

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

Due to migration, the value was transferred to one of the current document's attachments

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study is classified as reliable without restrictions because it is well documented and follows OECD Guideline 476.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)

GLP compliance:

yes (incl. QA statement)

Type of assay:

mammalian cell gene mutation assay

Species / strain / cell type:

Chinese hamster Ovary (CHO)

Details on mammalian cell type (if applicable):

- Periodically checked for Mycoplasma contamination: yes

Additional strain / cell type characteristics:

other: K1-BH4

Metabolic activation:

with and without

Metabolic activation system:

S9 from aroclor induced rat liver

Test concentrations with justification for top dose:

Migrated Data from field(s)
Field "Justification for deviation from the high dose level" (Path: ENDPOINT_STUDY_RECORD.GeneticToxicityVitro.MaterialsAndMethods.Method.JustificationForDeviationFromTheHighDoseLevel): 0, 0.132, 0.098, 0.063, 0.0362, 0.0122 ul/ml (analytical)

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: ethylmethanesulphonate 0.2 ul/ml without metabolic activation, benzo(a)pyrene 4 ug/ml with metabolic activation

Details on test system and experimental conditions:

METHOD OF APPLICATION: 7.5 ml of test substance was added to 17.5 ml of DMSO and vortexed for 2 min. The solution was allowed to separate, and the bottom DMSO/test substance layer and diluted further with DMSO. Appropriate amounts were then added to the test medium.


DURATION
- Preincubation period: 18-24 hrs at 37 degree C
- Exposure duration: 5 hrs at 37 degree C
- Expression time (cells in growth medium): 18-24 at 37 degree C

NUMBER OF REPLICATIONS: 2


DETERMINATION OF CYTOTOXICITY
Replicates from each treatment concentration were pooled and cultured in triplicate (100 cells/60 mm dish). After 7 days of incubation, colonies were fixed with methanol , stained with Giemsa, and counted. Determination was based on relative cloning efficiency.

Evaluation criteria:

mutant frequency > 20 mutants per 10^6 clonable cells, at least twice the mutant frequency of negative and solvent controls, mutant frequency above negative and solvent controls of at least 11 mutants per 10^6 clonable cells

Statistics:

Students t-test (p <= 0.05)

Key result

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

no cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

None of the mutant frequencies in the test groups were significantly elevated over negative and solvent controls. The test substance was cytotoxic at concentrations of 0.063 ul/ml or greater.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

CHO/HGPRT Mutation Assay

Dose (µl/ml)	Total Colonies	Cloning Efficiency	Total Mutant Colonies	Mutants/10^6 Clonable Cells
Without S9
Negative control	310	1.03	19	18.4
Solvent Control	329	1.10	6	5.5
0.132	284	0.95	0	5.3
0.098	260	0.87	0	5.8
0.063	321	1.07	0	0.9
0.0362	289	0.96	5	5.2
0.0122	294	0.98	12	12.2
Positive Control	282	0.94	227	241.5
With S9
Negative control	320	1.07	0	0.9
Solvent Control	330	1.10	1	0.9
0.132	299	1.00	0	1.0
0.098	299	0.99	0	1.0
0.063	256	0.85	4	4.7
0.0362	317	1.06	13	12.3
0.0122	293	0.98	13	13.3
Positive Control	239	0.80	91	114.2

Conclusions:

Interpretation of results: negative

The test substance is not mutagenic.

Executive summary:

This study determined the mutagenicity of commercial hexane to Chinese hamster ovary (CHO) cells. CHO cells were exposed to concentrations of 0, 0.132, 0.098, 0.063, 0.0362, or 0.0122 ul/ml both with and without metabolic activation for 5 hrs. The cells were then analyzed for mutation frequency. A concurrent cytotoxicity assay was performed. Results of the mutagenicity assay show that the test substance is not mutagenic both in the presence and absence of metabolic activation. However, the test substance was cytotoxic at concentrations of 0.063 ul/ml or greater.

Reference 3

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

Due to migration, the value was transferred to one of the current document's attachments

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study is classified as reliable without restriction because it followed a protocol comparable to OECD Guideline 473.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

GLP compliance:

yes (incl. QA statement)

Type of assay:

in vitro mammalian chromosome aberration test

Species / strain / cell type:

Chinese hamster Ovary (CHO)

Additional strain / cell type characteristics:

other: CHO-K1 cells

Metabolic activation:

with and without

Metabolic activation system:

S9 from aroclor induced rat liver

Test concentrations with justification for top dose:

Migrated Data from field(s)
Field "Justification for deviation from the high dose level" (Path: ENDPOINT_STUDY_RECORD.GeneticToxicityVitro.MaterialsAndMethods.Method.JustificationForDeviationFromTheHighDoseLevel): 0.015, 0.034, 0.074, 0.123, 0.416 ul/ml without S9
0.014, 0.022, 0.056, 0.118, 0.251 ul/ml with S9

Vehicle / solvent:

DMSO

Untreated negative controls:

yes

Negative solvent / vehicle controls:

yes

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: triethylenemelamine 0.5 ug/ml without S9, cyclophosphamide 50 ug/ml with S9

Details on test system and experimental conditions:

METHOD OF APPLICATION: 100 ul of dosing solutiong was added to the test medium


DURATION
- Preincubation period: 16-24 hrs at 37 degree C
- Exposure duration: 12 hrs without S9 at 37 degree in humidified air; 2 hrs with S9 at 37 degree in humidified air
- Expression time (cells in growth medium): For cells not treated with S9, two hours prior to cell harvest, treatment medium was removed and cells washed with PBS and refed with medium containing 0.1 ug/ml of Colcemid. For cells treated with S9, treatment medium was removed after exposure, cells were washed with PBS, refed, and returned to the incubator for 16 hrs. Colcemid was added at 0.1 ug/ml, and flasks incubated for two hrs.
- Fixation time (start of exposure up to fixation or harvest of cells): 14-20 hrs, collected by centrifugation



SELECTION AGENT (mutation assays):
SPINDLE INHIBITOR (cytogenetic assays):
STAIN (for cytogenetic assays): 5% Giemsa


NUMBER OF REPLICATIONS: 2


NUMBER OF CELLS EVALUATED: 100 per concentration


DETERMINATION OF CYTOTOXICITY
- Method: mitotic index and cell cycle delay


OTHER EXAMINATIONS:
Chromatid and isochromatid breaks, exchange figures, chromosome breaks, fragments, pulverized chromosomes, chromatid and isochromatid gaps


OTHER:

Evaluation criteria:

In order for the test to be valid, there must be no more than 6% cells with chromosome aberrations in the negative and solvent control groups. Positive control must be statistically increased over untreated controls (p<=0.05, Fisher's exact test). A positive result is percentage of cells with aberrations was statistically increased over untreated controls (p<=0.05, Fisher's exact test).

Statistics:

Fisher's exact test was used to determine statistical significance. Cochran-Armitage test was used to test dose-responsiveness.

Key result

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

>= 0.074 ul/ml

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Toxicity was observed at concentrations of 0.074 ul/ml or greater. No significant increase in chromosome aberrations was seen in treatment groups.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Results of CHO Chromosome Aberration Assay

Dose (µl/ml)	Mitotic Index	Cells Scored	Aberrations per cell (mean ± SD)	% Cells with Aberrations
Without S9
Negative Control	5.7	100	0.010 ± 0.100	1
Solvent Control	4.9	100	0.010 ± 0.100	1
0.015	4.8	100	0.000 ± 0.000	0
0.034	4.5	100	0.010 ± 0.100	1
0.074	2.9	100	0.010 ± 0.100	1
0.123	0.2	8	0.000 ± 0.000	0
0.416	0.0	0
Positive Control	2.2	100	0.360 ± 1.124	21
With S9
Negative Control	5.3	100	0.010 ± 0.100	1
Solvent Control	5.6	100	0.010 ± 0.100	1
0.014	5.3	100	0.010 ± 0.100	1
0.022	5.9	100	0.010 ± 0.100	1
0.056	3.1	100	0.010 ± 0.100	1
0.118	0.2	2	0.000 ± 0.000	0
0.251	0.0	0
Positive Control	2.5	100	0.840 ± 1.819	40

Conclusions:

Interpretation of results: negative

The test substance is not clastogenic.

Executive summary:

This study examined the potential for commercial hexane to cause chromosome aberrations in Chinese Hamster Ovary (CHO) cells. CHO cells were exposed to concentrations of 0, 0.015, 0.034, 0.074, 0.123, and 0.416 ul/ml without metabolic activation and 0, 0.014, 0.022, 0.056, 0.118, and 0.251 ul/ml with metabolic activation. 0.5 ug/ml triethylenemelamine was used a positive control without metabolic activation and 50 ug/ml cyclophosphamide was used as a positive control with metabolic activation. Negative and positive controls were valid. There was no significant increase in chromosome aberrations in any test group. The test substance was cytotoxic at concentrations of 0.074 ul/ml or greater. The test substance is not clastogenic.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

Migrated Data from field(s)
Field No-label (Path: ENDPOINT_SUMMARY.GeneticToxicity.KeyValueForChemicalSafetyAssessment.GeneticToxicityInVitro.DescriptionOfKeyInformation.KeyInfo): Content available as attachment under file "NoMigratedDataFor_26 May 2023 164434.html"
Field No-label (Path: ENDPOINT_SUMMARY.GeneticToxicity.KeyValueForChemicalSafetyAssessment.GeneticToxicityInVivo.DescriptionOfKeyInformation.KeyInfo): Content available as attachment under file "NoMigratedDataFor_26 May 2023 164434.html"

Link to relevant study records

Reference

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

1990

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: This study is classified as reliable without restriction because it closely followed OECD Guideline 475.

Justification for type of information:

A discussion and report on the read across strategy is given as an attachment in IUCLID Section 13.

Reason / purpose for cross-reference:

read-across: supporting information

Reason / purpose for cross-reference:

reference to same study

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 475 (Mammalian Bone Marrow Chromosome Aberration Test)

Deviations:

yes

Remarks:

In order to test substance as a vapor, animals were exposed via nose-only inhalation.

GLP compliance:

yes (incl. QA statement)

Type of assay:

other: cytogenetics assay

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Sprague Dawley, Inc., Frederick, MD
- Age at study initiation: 6-8 weeks
- Weight at study initiation: 228-266 g males, 153-188 g females
- Assigned to test groups randomly: assigned using body weight randomization program
- Housing: singly in plastic cages, identified by ear tags
- Diet (e.g. ad libitum): certified laboratory rodent chow, ad libitum
- Water (e.g. ad libitum): tap water ad libitum
- Acclimation period: 10 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 72 degree F
- Humidity (%): 40-70
- Photoperiod (hrs dark / hrs light): 12 hrs light/12 hrs dark

Route of administration:

inhalation: vapour

Details on exposure:

TYPE OF INHALATION EXPOSURE: nose only


GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: 360 ml polycarbonate chamber
- Method of holding animals in test chamber: Polycarbonate tubes were used to restrain the animals. Only the nose of the animals protruded into the chambers. A soft sponge was used as a plunger to hold the animals in place.
- Source and rate of air: filtered outside air
- Method of conditioning air: A Gilson peristaltic pump was used to meter test liquid in sealed resevoirs to vaporization flasks immersed in 57 degree C water. Air was passed through the flasks, then through teflon tubing to the exposure chamber. A calibrated rotameter was used to dilute the air to the appropriate concentration.
- Temperature, humidity, pressure in air chamber: monitored every 30 min.
- Air flow rate: monitored every 30 min.


TEST ATMOSPHERE
- Brief description of analytical method used: GC
- Samples taken from breathing zone: yes

Duration of treatment / exposure:

6 hrs per day

Frequency of treatment:

5 days

Post exposure period:

1 or 19 hrs after end of exposure

Remarks:

Doses / Concentrations:
0, 900, 3000, 9000 ppm (0, 3168, 10560, 31680 mg/m3)
Basis:
nominal conc.

No. of animals per sex per dose:

5 male and 5 female per dose

Control animals:

yes, sham-exposed

Positive control(s):

triethylenemelamine
- Route of administration: intraperitoneal injection
- Doses / concentrations: 0.5 mg/kg

Tissues and cell types examined:

bone marrow

Details of tissue and slide preparation:

TREATMENT AND SAMPLING TIMES ( in addition to information in specific fields):
Colchicine was administered two hours prior to sacrifice to arrest cell division at metaphase. Animals were sacrificed by carbon dioxide asphyxiation. Bone marrow cells were removed from the femur by aspiration into HBSS. Cells were mixed well and kept in an ice bath until all samples were collected. After centrifuging for 10 min, the supernatent was discarded, and the cells resuspended in 5 ml 0.075 M KCl at 37 degree C. After incubating for 10 min, cells were again centrifuged and resuspended in fixative. This was repeated with fresh fixative.

DETAILS OF SLIDE PREPARATION:
Cells were again centrifuged for 10 min, the supernantant decanted, and the cells resuspended in 1 ml of fixative. Two drops were placed on a cold wet glass slide, and allowed to air dry. Three slides were prepared per animal. Slides were stained with 4% Giemsa.

METHOD OF ANALYSIS:
50 metaphase cells containing approx. 40 centromeres were scored if possible.

OTHER:

Evaluation criteria:

In order for the test to be valid, there must be no more than 4% cells demonstrating aberrations in the negative control group. Positive control must be statistically increased over untreated controls (p<=0.05, Fisher's exact test). A positive result is a percentage of cells with aberrations which was statistically increased over untreated controls (p<=0.05, Fisher's exact test).

Statistics:

Fisher's exact test was used to determine statistical significance. Cochran-Armitage test was used to test dose-responsiveness.

Key result

Sex:

male/female

Genotoxicity:

negative

Toxicity:

no effects

Vehicle controls validity:

not applicable

Negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

There was a decrease in body weight observed after the last exposure. This reduction is typical for nose-only exposure, and is considered to be due to restraint. There was no statistically significant increase in aberrations in the exposure groups.

Chromosomal Damage in Rat Bone Marrow - Male         

Dose (ppm)	Time Evaluated (hrs)	Cells with Aberrations (%)	Mean Aberrations per Cell per Animal
0	6	0.0	0.000 ± 0.000
0	24	0.0	0.000 ± 0.000
876	6	0.4	0.004 ± 0.009
876	24	0.0	0.000 ± 0.000
3249	6	0.0	0.000 ± 0.000
3249	24	0.4	0.004 ± 0.009
8715	6	0.8	0.008 ± 0.018
8715	24	0.4	0.004 ± 0.009
Positive Control	6	14.4	0.696 ± 0.121

Chromosomal Damage in Rat Bone Marrow - Female

Dose (ppm)	Time Evaluated (hrs)	Cells with Aberrations (%)	Mean Aberrations per Cell per Animal
0	6	0.8	0.008 ± 0.011
0	24	0.0	0.000 ± 0.000
876	6	0.4	0.004 ± 0.009
876	24	0.4	0.004 ± 0.009
3249	6	0.4	0.004 ± 0.009
3249	24	0.0	0.000 ± 0.000
8715	6	0.4	0.004 ± 0.009
8715	24	0.4	0.004 ± 0.009
Positive Control	6	20.8	0.900 ± 0.477

Conclusions:

Interpretation of results: negative
The test substance is not mutagenic.

Executive summary:

This study determined the effect of inhalation exposure of commercial hexane on rat bone marrow. Groups of 5 male and 5 female rats were exposed to 0, 900, 3000, and 9000 ppm of test substance vapor for 6 hrs/day for 5 days. 0.5 mg/kg triethylenemelamine was used as a positive control substance. Animals were sacrificed 3 or 21 hrs after exposure, and the bone marrow from their femurs examined for cell aberrations. There was no statistically significant increase in cell aberrations in any treatment group. The test substance is not mutagenic.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

There is no data available forHydrocarbons, C6, isoalkanes, <5% n-hexane. However, data is available for a structural analogue, commercial hexaneand presented in the dossier. This data is read across toHydrocarbons, C6, isoalkanes, <5% n-hexanebased on analogue read across and a discussion and report on the read across strategy is provided as an attachment in IUCLID Section 13.

 

In Vitro

 

In vitro gene mutation study in bacteria

 

Commercial Hexane

 

A key study (API, 1989) examined the mutagenicity of vapors of the test substance commercial hexane. Plates of S. typhimurium were exposed for 7 -8 hrs to test atmospheres of 0, 600, 1000, 3000, 6000, or 9000 ppm of test substance. 20,000 ppm of 1,1 -dichloroethene was used a vapor-phase positive control substance. The test substance did not produce a positive response in any of the test strains. The test substance is not mutagenic.

 

In Vitro Chromosome Aberration in Mammalian Cells

 

Commercial Hexane

 

A key study (Daughtery et al., 1994) examined the potential for commercial hexane to cause chromosome aberrations in Chinese Hamster Ovary (CHO) cells. CHO cells were exposed to concentrations of 0, 0.015, 0.034, 0.074, 0.123, and 0.416 uL/mL without metabolic activation and 0, 0.014, 0.022, 0.056, 0.118, and 0.251 uL/mL with metabolic activation. 0.5 ug/mL triethylenemelamine was used a positive control without metabolic activation and 50 ug/mL cyclophosphamide was used as a positive control with metabolic activation. Negative and positive controls were valid. There was no significant increase in chromosome aberrations in any test group. The test substance was cytotoxic at concentrations of 0.074 uL/mL or greater. The test substance is not clastogenic.

 

In Vitro Gene Mutation study in Mammalian Cells

 

Commercial Hexane

 

A key study (API, 1990) determined the mutagenicity of commercial hexane to Chinese hamster ovary (CHO) cells. CHO cells were exposed to concentrations of 0, 0.132, 0.098, 0.063, 0.0362, or 0.0122 uL/mL both with and without metabolic activation for 5 hrs. The cells were then analyzed for mutation frequency. A concurrent cytotoxicity assay was performed. Results of the mutagenicity assay show that the test substance is not mutagenic both in the presence and absence of metabolic activation. However, the test substance was cytotoxic at concentrations of 0.063 uL/mL or greater.

 

In Vivo

 

Commercial Hexane

 

A key study (Daughtery et al., 1994) determined the effect of inhalation exposure of commercial hexane on rat bone marrow. Groups of 5 male and 5 female rats were exposed to 0, 900, 3000, and 9000 ppm of test substance vapor for 6 hrs/day for 5 days. 0.5 mg/Kg triethylenemelamine was used as a positive control substance. Animals were sacrificed 3 or 21 hrs after exposure, and the bone marrow from their femurs examined for cell aberrations. There was no statistically significant increase in cell aberrations in any treatment group.The test substance is not mutagenic.

Justification for classification or non-classification

The negative results observed in read across in vitro and in vivo genotoxicity assays do not warrant the classification of Hydrocarbons, C6, isoalkanes, <5% n-hexane as a genotoxin under the new Regulation (EC) 1272/2008 on classification, labeling and packaging of substances and mixtures (CLP).