Methanol

Carcinogenicity

Description of key information

Several studies showed carcinogenicity for mouse and rat via oral or inhalation route. The studies have been callenged and can therefore not be transferred to humans.

Key value for chemical safety assessment

Carcinogenicity: via oral route

Link to relevant study records

Reference

Reference 1

Endpoint:

carcinogenicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

secondary literature

Remarks:

secondary source; original data not available

Principles of method if other than guideline:

no data

GLP compliance:

not specified

Species:

mouse

Strain:

Swiss

Sex:

male/female

Route of administration:

oral: gavage

Duration of treatment / exposure:

lifetime

Frequency of treatment:

6 days per week

Remarks:

Doses / Concentrations:
560, 1000 and 2100 mg/kg/d (female); 550, 970 and 1800 mg/kg/d (male)
Basis:

Details on results:

Increased incidence of liver parenchymal cell necrosis and malignant lymphomas.

Key result

Dose descriptor:

LOAEL

Effect level:

> 1 800 - < 2 100 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: overall effects

Remarks on result:

other: Effect type: carcinogenicity (migrated information)

Key result

Critical effects observed:

no

Reference 2

Endpoint:

carcinogenicity: oral

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

significant methodological deficiencies

Remarks:

basic information given, selected doses were too high for human tolerability; other authors have severly challenged the validity of the study (Cruzan, 2009; http://www.epa.gov/iris/ramazzini.htm; EFSA 2013)

Principles of method if other than guideline:

Because of the expansion in the use and diffusion of ethyl alcohol in the workplace and environment and the lack of adequate experimental data to evaluate its carcinogenicity, experiments on ethyl alcohol described herein were performed.

GLP compliance:

not specified

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Age: 8 weeks old at beginning of the study
Animals were kept under observation until spontaneous death.
Animals were identified by ear punch and housed in groups of five in makrolon cages (41 x 2S x 15 cm) with a stainless steel wire top; a shallow layer of white wood shavings served as bedding. The animals were kept in a single room at 23 ± 2°C and 50-60% relative humidity.

Route of administration:

oral: drinking water

Vehicle:

water

Duration of treatment / exposure:

104 weeks

Frequency of treatment:

daily ad libitum

Remarks:

Doses / Concentrations:
500, 5000, 20000 ppm
Basis:

No. of animals per sex per dose:

n = 100

Control animals:

yes, concurrent vehicle

Observations and examinations performed and frequency:

Each morning, residual liquids from the previous day were removed, and the glass drinking bottles were washed and filled with fresh solution. Mean daily drinking water and feed consumption and weight were determined once weekly for the first 13 weeks and then every 2 weeks for 104 weeks. Thereafter, animals were weighed every 8 weeks until the end of the experiment. Status and behavior of animals were examined 3 times daily, and they were submitted to clinical examination for gross changes every 2 weeks.

Sacrifice and pathology:

Upon death, animals underwent systematic necropsy. Histopathology was routinely performed on the following organs and tissues: skin and subcutaneous tissue, brain, pituitary gland, Zymbal glands, parotid glands, submaxillary glands, Harderian glands, cranium (with oral and nasal cavities und extemal and internal ear ducts) (5 seetions of head) , tangue, thyroid and parathyroid, pharynx, larynx, thymus and mediastinal lymph nodes, trachea, lung and mainstem bronchi, heart, diaphragm, Iiver, spleen, pancreas, kidneys, adrenal glands, esophagus, stomach (fore and glandular), intestine (four levels), urinary bladder, prostate, gonads, interscapular fat pad, subcutaneous and mesenteric Iymph nodes, and any other organs or tissues with pathologic lesions. All slides were examined microscopically by the same group of pathologists; a senior pathologist reviewed all tumors and any other lesion of oncologic interest. All pathologists followed the same criteria of histopathological evaluation and classification. Multiple tumors of different type and site, of different type in the same site, of the same type in bilateral organs, of the same type in the skin, in the subcutaneous tissue, and in mammary glands, or at distant sites of diffuse tissue (i.e., bones and skeletal muscle) were plotted as single/independent tumors. Multiple tumors of the same type in the same tissue and organ (including those of the bilateral organs) were plotted only once.

Statistics:

Statistical analysis was perforrned using the X2 test to evaluate differences in tumor incidence between treated and control groups. The Cochrane Armitage test was used to evaluate dose-response relations.

Clinical signs:

no effects observed

Description (incidence and severity):

No behavioral changes were observed.

Mortality:

no mortality observed

Description (incidence):

No mortality were observed.

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

A slight increase was observed in the body weight of males and, to a lesser extent, of females treated with the highest dose.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

There were no noteworthy changes in feed consumption.

Water consumption and compound intake (if drinking water study):

effects observed, treatment-related

Description (incidence and severity):

There were no noteworthy changes in beverage apart from a decrease in water consumption in females treated with the highest dose between 8 and 56 weeks of age.

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

No treatment-related nononcologic pathological changes were detected by gross inspection.

Description (incidence and severity):

No treatment-related nononcologic pathological changes were detected by histopathological examination.

Histopathological findings: neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Differences observed between treated and contral animals were: (l) a dose-related increase of total malignant tumors in males and females of treated groups; (2) a dose-related increase of carcinomas of the head and neck, mainly in the ear ducts, in males of treated groups and in females treated with 20000 and 5000 ppm; (3) a statistically significant increase (P <0.01) of testicular interstitial cell hyperplasias and adenomas in the group treated with the highest dose; (4) an increase in sarcomas ofthe uterus at the highest dose; (5) a dose-related increase in osteosarcomas of the head in males and females ofthe treated groups; and (6) a dose-related increase in hemolymphoreticular neoplasias in males and females of the treated groups.

Relevance of carcinogenic effects / potential:

The US Environmental Protection Agency (EPA) considers data on lymphomas and leukemias from the study as unreliable (http://www.epa.gov/iris/ramazzini.htm). The European Food Safety Authority (EFSA) Panel on Food Additives and Nutrient Sources added to Food (ANS) does not support the validity of the findings and agrees with concerns identified by an EPA sponsored Pathology Working Group (EFSA, DRAFT Scientific Opinion on the re-evaluation of aspartame (E 951) as a food additive, 2013).

Key result

Dose descriptor:

NOAEL

Effect level:

> 466 - < 529 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: overall effects

Remarks on result:

other: Effect type: carcinogenicity (migrated information)

Key result

Dose descriptor:

LOAEL

Effect level:

> 1 872 - < 2 101 mg/kg bw/day

Sex:

male/female

Basis for effect level:

other: overall effects

Remarks on result:

other: Effect type: carcinogenicity (migrated information)

Key result

Critical effects observed:

no

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LOAEL

1 800 mg/kg bw/day

Species:

mouse

Quality of whole database:

The validity of the study has been challenged (Cruzan, 2009; http://www.epa.gov/iris/ramazzini.htm; EFSA DRAFT Scientific Opinion on the re-evaluation of aspartame (E 951) as a food additive, 2013) due to early mortality and it was concluded that methanol is not likely to be carcinogenic in humans.

Carcinogenicity: via inhalation route

Link to relevant study records

Reference

Reference 1

Endpoint:

carcinogenicity: inhalation

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 453 (Combined Chronic Toxicity / Carcinogenicity Studies)

Deviations:

yes

Remarks:

Not all parameters mentioned in the guideline were investigated.

Principles of method if other than guideline:

According to OECD Guideline for Chronic Toxicity, Oct. 1980. Comprehensive study programme on three species (rat, mouse, monkey) including metabolic, pharmacokinetic, short-, long-term, reproduction and carcinogenicity studies.

GLP compliance:

not specified

Species:

mouse

Strain:

B6C3F1

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 6 weeks
- Housing: individually in wire-mash cages attached to the inhalation chamber
TEST ANIMALS
- Source: Charles River Japan Inc.
- Age at study initiation: 6 wks
- Weight at study initiation: approx. means: males 23 g, females 19 g (taken from graph)
- Fasting period before study: no
- Housing: individually
- Diet (e.g. ad libitum): solid chow (CRF-1, Charles River Japan Inc.) ad libitum
- Water (e.g. ad libitum): sterile-filtered and UV-irradiated tap water ad libitum
- Acclimation period: 5 days of quarantine + 6 days in inhalation chamber


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±2
- Humidity (%): 55±15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

inhalation: vapour

Type of inhalation exposure (if applicable):

whole body

Vehicle:

unchanged (no vehicle)

Details on exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Whole-body exposure chambers (Hazleton 1000 Inhalation Exposure Chamber, 2.5 m³ inner volume)
- Method of holding animals in test chamber: individual rooms in stainless steel wire mesh inhalation cages (60 rooms) installed in the chamber
- Source and rate of air: external air
- Method of conditioning air: successively passed through a medium performance, a high performance, and an activated carbon filter, temperature and humidity regulated
- System of generating particulates/aerosols: total vaporizer, fed by a microquantification pump regulated by a feed back mechanism coupled to a methanol gas analyzer, which measures the concentration in the chamber
- Temperature, humidity, pressure in air chamber: 24±2°C, 55±15%
- Air flow rate: no data
- Air change rate: 15/h
- Method of particle size determination: not applicable, vapor


TEST ATMOSPHERE
- Brief description of analytical method used: Photometric determination by an infra-red spectrophotometer
- Samples taken from breathing zone: no

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analytical values were close to nominal ones, no further data.

Duration of treatment / exposure:

18 months

Frequency of treatment:

continuously, approx. 19 h/d

Post exposure period:

none

Remarks:

Doses / Concentrations:
0.013, 0.13, 1.3 mg/L (corresponding to 10, 100, 1000 ppm); 10436 - 10550 h (males), 10573 - 10642 h (females)
Basis:
nominal conc.

No. of animals per sex per dose:

52 males, 53 females

Control animals:

yes, sham-exposed

Details on study design:

- Dose selection rationale: Exposure levels selected on the basis of a 4-wk preliminary exposure study

Positive control:

No

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: at least once a day, 5-6 days/wk
- Cage side observations included: mortality, abnormal appearance and behaviour

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: at least weekly

BODY WEIGHT: Yes
- Time schedule for examinations: once per week

FOOD CONSUMPTION: Yes
Food consumption during a week by 2 animals was measured on 24 animals/sex/group, daily food consumption per animal was then calculated.
- Time schedule: weekly during first 13 wks of exposure, monthly thereafter

FOOD EFFICIENCY: No

OPHTHALMOSCOPIC EXAMINATION: Yes (grossly visible signs)
- Time schedule for examinations: weekly
- Dose groups that were examined: all


HAEMATOLOGY: Yes
- Time schedule for collection of blood: at necropsy
- Anaesthetic used for blood collection: No
- Animals fasted: No
- How many animals: all
- Parameters examined: erythrocyte count, leukocyte count, hemoglobin concentration, platelet count, hematocrit value, differential leukocyte count


CLINICAL CHEMISTRY: Yes, from about 20 animals/sex/group
- Time schedule for collection of blood: at necropsy
- Animals fasted: No
- How many animals: all
- Parameters examined: blood methanol levels, GOT, GPT, LDH, ALP, urea nitrogen, glucose, total cholesterol, calcium, inorganic phosphorus, triglyceride, total protein, A/G ratio


URINALYSIS: Yes, from about 20 animals/sex/group
- Time schedule for collection of urine: on a day shortly before sacrifice, not further specified
- Metabolism cages used for collection of urine: No data
- Animals fasted: No
- Parameters examined: glucose, pH, protein, ketones, bilirubin, occult blood, urobilinogen, intensity of coloring


NEUROBEHAVIOURAL EXAMINATION: No

OTHER: Organ weight, organ/body weight ratio
-Time schedule: at sacrifice of scheduled animals
- Organs: brain, heart, lung, liver, kidney, spleen, testis

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, macroscopic changes of each organ
HISTOPATHOLOGY: Yes:
Brain, Pituitary, Thyroid, Heart, Lung, Trachea, Liver, Thymus, Kidney, Spleen, Pancreas, Adrenal, Testis, Prostate, Seminal vesicle, Ovary, Uterus, Vagina, Urinary bladder, Esophagus, Stomach, Duodenum, Jejunum, Ileum, Cecum, Colon, Rectum, Femur and bone-marrow, Mesenteric lymph node, Salivary glands (parotid, submaxillary, sublingual), Sciatic nerve, Eyes, Lacrimal gland, Optic nerve, Muscle, Spinal cord, Mammary gland, Hilar lymph node, Submaxillary lymph node, Paranasal cavity, Pharynx, Larynx, Skin, Any other tissues with lesions.

Statistics:

All data obtained were analyzed by t-test, Fischer's exact test or Armitage's chi²-test.

Clinical signs:

no effects observed

Description (incidence and severity):

No abnormalities of the general state could be observed in treated animals.

Mortality:

mortality observed, treatment-related

Description (incidence):

Survival was high without significant differences as compared to the control, mortality ranging between no deaths and 7.5% deaths by the end of the study: 0% (1000 ppm males, 10 ppm females), 2% (controls), 6% (10 and 100 ppm males) and 7.5% (100 and 1000 pm females).

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Body weight was somewhat increased in treated group, significantly in 1000 ppm males, between months 6 through 12 in males and months 9 through 12 in females.

Ophthalmological findings:

not specified

Haematological findings:

effects observed, non-treatment-related

Description (incidence and severity):

There was no evidence of a treatment-related effect in blood parameters.

Clinical biochemistry findings:

effects observed, non-treatment-related

Description (incidence and severity):

There was no evidence of a treatment-related effect in clinical parameters. Biochemical examination of plasma gave abnormal values for animals which were found to have tumoral changes at histopathological examination

Urinalysis findings:

effects observed, non-treatment-related

Description (incidence and severity):

There was no evidence of a treatment-related effect in urinalysis parameters.

Organ weight findings including organ / body weight ratios:

effects observed, treatment-related

Description (incidence and severity):

For males, the mean testis weight of the 1000 ppm group was lower than that of controls, significant differences were found for absolute value and ratio to body weight due to severe testis atrophy in one male. For females, the kidney weight of the 1000 ppm group was significantly higher than in controls, but there was no significant difference for its ratio to body weight. There were no significant differences for any other organs in the mid- and high-dose groups.

Gross pathological findings:

effects observed, non-treatment-related

Description (incidence and severity):

Higher incidence was noticed in such changes as the swelling of spleen, node in the lung, node in the liver, swelling of preputial gland, ovarian cyst and swelling of uterus. Among these changes, the node in the liver and ovarian cyst were observed with significantly higher incidence, the swelling of spleen with significantly lower incidence, in females in the high-dose group. These changes, however, did not show clear dose-dependency and were considered to be accidental.

Histopathological findings: non-neoplastic:

no effects observed

Description (incidence and severity):

Non-neoplastic organ findings were similar to those commonly found in the control animals of 12 months.

Histopathological findings: neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Individual tumor frequencies showed no significant differences between all groups; there was no difference in the severity of tumors between the groups. The tumors exclusively observed in the 1000-ppm group were all within the spontaneous range and included fatty cell tumor at the submaxillary lymph node (1/52 males), chromophobe adenoma of the pituary gland (3/52 females), adrenal pheochromocytoma (1/52 females), dermal fibrosarcoma (1/52 males), and meningeal sarcoma (1/52 females) vs. 0/52 in all other groups. The spontaneous liver-tumors rate naturally high in this species was not increased by methanol treatment.

Other effects:

no effects observed

Description (incidence and severity):

The blood levels of methanol and formate were not measured.

Key result

Dose descriptor:

NOAEC

Effect level:

>= 1.3 mg/L air

Sex:

male/female

Remarks on result:

other: Effect type: carcinogenicity (migrated information)

Key result

Critical effects observed:

no

Exposure per day was 19 h, which implies that prolonged steady-state blood levels were reached which even may have been higher than in studies using the same exposure concentration, but shorter exposure times.

CONCLUSION

The result gave no evidence of a cancerogenic potential of methanol in mice.

Reference 2

Endpoint:

carcinogenicity: inhalation

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 453 (Combined Chronic Toxicity / Carcinogenicity Studies)

Deviations:

yes

Remarks:

Not all parameters mentioned in the guideline were investigated

Principles of method if other than guideline:

According to OECD Guideline for Chronic Toxicity, Oct. 1980. Comprehensive study programme on three species (rat, mouse, monkey) including metabolic, pharmacokinetic and short-, long-term, reproduction and carcinogenicity studies.

GLP compliance:

not specified

Species:

rat

Strain:

Fischer 344/DuCrj

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: 6 weeks
- Housing: individually in wire-mash cages attached to the inhalation chamber
TEST ANIMALS
- Source: Charles River Japan Inc.
- Age at study initiation: 6 wks
- Weight at study initiation: approx. means: males 120 g, females 100g (taken from graph)
- Fasting period before study: no
- Housing: individually
- Diet (e.g. ad libitum): solid chow (CRF-1, Charles River Japan Inc.) ad libitum
- Water (e.g. ad libitum): sterile-filtered and UV-irradiated tap water ad libitum
- Acclimation period: 1 wk of quarantine + 6 days in inhalation chamber


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22±2
- Humidity (%): 55±15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

inhalation: vapour

Type of inhalation exposure (if applicable):

whole body

Vehicle:

unchanged (no vehicle)

Details on exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Whole-body exposure chambers (Hazleton 1000 Inhalation Exposure Chamber, 2.5 m³ inner volume)
- Method of holding animals in test chamber: individual rooms in stainless steel wire mesh inhalation cages (24 rooms) installed in the chamber
- Source and rate of air: external air
- Method of conditioning air: successively passed through a medium performance, a high performance, and an activated carbon filter, temperature and humidity regulated
- System of generating particulates/aerosols: total vaporizer, fed by a microquantification pump regulated by a feed back mechanism coupled to a methanol gas analyzer, which measures the concentration in the chamber
- Temperature, humidity, pressure in air chamber: 24±2°C, 55±15%
- Air flow rate: no data
- Air change rate: 15/h
- Method of particle size determination: not applicable, vapor


TEST ATMOSPHERE
- Brief description of analytical method used: Photometric determination by an infra-red spectrophotometer
- Samples taken from breathing zone: no

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

Analytical values were close to nominal ones, no further data.

Duration of treatment / exposure:

24 months

Frequency of treatment:

continuously, 20 h/d

Post exposure period:

none

Remarks:

Doses / Concentrations:
0.013, 0.13, 1.3 mg/l (corresponding to 10, 100, 1000 ppm): 14255 - 14323 h (males; 14407 - 14468 h (females)
Basis:
nominal conc.

No. of animals per sex per dose:

52

Control animals:

yes, sham-exposed

Details on study design:

- Dose selection rationale: Exposure levels selected on the basis of a 4-wk preliminary exposure study

Positive control:

No

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: at least once a day, 5-6 days/wk
- Cage side observations included: mortality, abnormal appearance and behaviour

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: at least weekly

BODY WEIGHT: Yes
- Time schedule for examinations: once per week

FOOD CONSUMPTION: Yes
Food consumption during a week by 2 animals was measured on 24 animals/sex/group, daily food consumption per animal was then calculated.
- Time schedule: weekly during first 13 wks of exposure, monthly thereafter

FOOD EFFICIENCY: No

OPHTHALMOSCOPIC EXAMINATION: Yes (grossly visible signs)
- Time schedule for examinations: weekly
- Dose groups that were examined: all


HAEMATOLOGY: Yes
- Time schedule for collection of blood: at necropsy
- Anaesthetic used for blood collection: No
- Animals fasted: No
- How many animals: all
- Parameters examined: erythrocyte count, leukocyte count, hemoglobin concentration, platelet count, hematocrit value, differential leukocyte count


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at necropsy
- Animals fasted: No
- How many animals: all
- Parameters examined: blood methanol levels, GOT, GPT, LDH, γ-GTP, ALP, blood urea nitrogen, glucose, total cholesterol, calcium, inorganic phosphorus, triglyceride, total protein, A/G ratio, sodium, potassium, chloride


URINALYSIS: Yes
- Time schedule for collection of urine: on a day shortly before sacrifice, not further specified
- Metabolism cages used for collection of urine: No data
- Animals fasted: No
- Parameters examined: glucose, pH, protein, ketones, bilirubin, occult blood, urobilinogen, intensity of coloring


NEUROBEHAVIOURAL EXAMINATION: No

OTHER: Organ weight, organ/body weight ratio
-Time schedule: at sacrifice of scheduled animals
- Organs: brain, pituitary, thyroid, thymus, heart, lung, liver, kidney, spleen, adrenal, testis (ovary)

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, macroscopic changes of each organ
HISTOPATHOLOGY: Yes:
Brain, Pituitary, Thyroid, Heart, Lung, Trachea, Liver, Thymus, Kidney, Spleen, Pancreas, Adrenal, Testis, Prostate, Seminal vesicle, Ovary, Uterus, Vagina, Urinary bladder, Esophagus, Stomach, Duodenum, Jejunum, Ileum, Cecum, Colon, Rectum, Femur and bone-marrow, Mesenteric lymph node, Salivary glands (parotid, submaxillary, sublingual), Sciatic nerve, Eyes, Lacrimal gland, Optic nerve, Muscle, Spinal cord, Mammary gland, Hilar lymph node, Submaxillary lymph node, Paranasal cavity, Pharynx, Larynx, Skin, Any other tissues with lesions.

Statistics:

All data obtained were analyzed by t-test, Fischer's exact test or Armitage's chi²-test.

Clinical signs:

no effects observed

Description (incidence and severity):

No abnormalities of the general state could be observed in treated animals.

Mortality:

mortality observed, non-treatment-related

Description (incidence):

19.2 to 34.6 % of males and 32.7 to 40.4 % of females died or had to be sacrificed in extremis. There were no significant differences from the control groups.

Body weight and weight changes:

effects observed, non-treatment-related

Description (incidence and severity):

Body weight was somewhat but not significantly retarded between weeks 51 through 72 in the high-dose females (1000 ppm).

Food consumption and compound intake (if feeding study):

effects observed, treatment-related

Description (incidence and severity):

A significant inhibition was noted for high-dose males from week 30 to 52.

Ophthalmological findings:

not examined

Description (incidence and severity):

Not reported.

Haematological findings:

no effects observed

Description (incidence and severity):

No changes were evident in haematological parameters.

Clinical biochemistry findings:

no effects observed

Description (incidence and severity):

No changes were evident in biochemical parameters.

Urinalysis findings:

effects observed, treatment-related

Description (incidence and severity):

Urinanalysis revealed a significant increase in glucose in 1000ppm-males, and in females a significant decrease in pH (1000 ppm) and increase in bilirubin (100 and 1000 ppm), but individual values were within normal range.

Organ weight findings including organ / body weight ratios:

no effects observed

Description (incidence and severity):

None of the organs examined showed significant differences in absolute weight or organ/body weight ratios.

Gross pathological findings:

effects observed, treatment-related

Description (incidence and severity):

Changes showing significant differences included an increase of nodes in the lung in high-dose males, coinciding with papillary adenoma or adematoid. Further changes concerned differences in depression of brain for mid-dose males, nodes in the liver and swelling of the pituitary and thyroid for females, they were considered to be accidental.

Histopathological findings: non-neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

Non-neoplastic findings were similar to those commonly found in the control animals of 24 months. Significant diferences were observed for the kidney of both sexes, the lung of males, and all organs except adrenal of females in the low- and mid-dose groups. They were all considered not treatment-related.

Histopathological findings: neoplastic:

effects observed, non-treatment-related

Description (incidence and severity):

There was no dose-dependence of tumour development for papillary adenomas, adematoids and the sum of both in males. The spontaneous tumor rate of the Fischer strain in this laboratory and in the published literature was in the range of 14 %. Therefore, the tumours are unlikely to be treatment-related.

No clear dose-dependence was noted for adrenal chromaffinomas in females, but at the highest dose the number of animals with this kind of tumors was significantly increased and was higher than the spontaneous rate published for the Fischer strain (3.2 - 3.5 %) [Note: not clear whether the given data relate only to females or to both sexes. It should be noted that the spontaneous rate of male rats was high in this test compared with that of females.]

A higher incidence of hyperplastic changes in the testes was observed in high-dose males (19.2 %), but no conclusions on dose-dependence could be made as only control and high-dose males were examined.

Overall, tumor frequencies showed no significant differences between all groups. There was no evidence of an increase in liver tumors. Specific tumours appeared at a somewhat higher incidence in high-dose groups of both sexes:
- papillary lung adenomas in males (without dose relationship and not statistically significant: 6/52 vs. 1/52 in the control ), but not in females
- adrenal phaeochromocytomas in females (based on Fisher´s Exact Test: not statistically significant: 7/51 vs. 2/50), but not in males
- 3/52 and 5/52 metastatic (transition) tumors of common origin in males and females, respectively (originated from tumours prone to metatasis). These events having emerged after week 79 and 104 were considered incidental and not treatment-related.

Other effects:

no effects observed

Description (incidence and severity):

The blood levels of methanol were measured but not documented in detail (reported to be similar to those found in the two-generation study). Blood dose levels in the low-dose (10 ppm) and mid-dose (100 ppm) group were almost comparable to those in the control group. In the high-dose group (1000 ppm), however, they were 54 ppm for males and 88 ppm for females. Formate was not measured. Note: Exposure per day was 20 h, which implies that prolonged steady-state blood levels were reached which even may have been higher than in studies using the same exposure concentration, but shorter exposure times.

Key result

Dose descriptor:

NOAEC

Effect level:

>= 1.3 mg/L air

Sex:

male/female

Remarks on result:

other: Effect type: carcinogenicity (migrated information)

Key result

Critical effects observed:

no

NEOPLASTIC CHANGES:

Incidences (number of tumor-bearing animals/total animals):

Males	0	0.013	0.13	1.3 mg/L
A	1/52	5/50	2/52	6/52
B	4/52	1/50	5/52	4/52
A + B	5/52	6/50	7/52	10/52
C	7/52	--	--	4/41
D	4/52			10/52

-- = not examined

A) Papillary adenomas (males)

B) Adematoids = hyperplastic changes (pre-neoplastic, lung) (males)

C) Adrenal chromaffinoma (males)

D) Testis hyperplastic changes (males)

Females	0	0.013	0.13	1.3 mg/L
A	2/52	--	--	2/52
B	3/52	--	--	1/52
A + B	5/52	--	--	3/52
C	2/50	3/51	2/49	7/51

-- = not examined

A) Papillary adenomas (females)

B) Adematoids = hyperplastic changes (pre-neoplastic) (females)

C) Adrenal chromaffinoma (females)

CONCLUSION

The results gave no evidence of a clearly cancerogenic potential of methanol in rats. The biological significance of the increase in the incidence of the phaeochromocytomas in the aged female high-dose rats is considered to be low.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEC

1 300 mg/m³

Study duration:

chronic

Species:

mouse

Justification for classification or non-classification

Classification, Labelling, and Packaging Regulation (EC) No 1272/2008
The available experimental test data are reliable and suitable for classification purposes under Regulation (EC) No 1272/2008. In mouse and rat effects were shown, but can not be transfered to humans. As a result the substance is not considered to be classified for carcinogenicity under Regulation (EC) No 1272/2008, as amended for the tenth time in Regulation (EU) No 2017/776.

Additional information

Methanol was investigated for chronic toxicity and carcinogenicity in two long-term whole-body inhalation studies (24 months in rats and 18 months in mice for 20 and 19 hours per day, respectively). There was no evidence of a carcinogenic potential in rats and mice exposed to air concentrations of up to 1.3 mg/L.

Overall tumour frequencies showed no statistically significant differences between treatment groups and controls in either rats or mice. There was a non-statistically significant increase in phaeochromocytoma incidence among aged female high-dose rats; the biological significance of this observation was considered to be low. On balance, these results did not suggest that methanol is carcinogenic in rodents from this exposure route.

In studies with oral administration in rats (drinking water; Soffritti et al., 2002) and mice (gavage; Apaja, 1980) the number of tumor-bearing animals in the rat study showed a clear dose-related trend. Target organs were less pronounced (some indication of ear duct tumors, osteosarcomas and lymphoid tumors); the authors postulate a multi-site potential for carcinogenicity. The validity of the study has been challenged (Cruzan, 2009; http://www.epa.gov/iris/ramazzini.htm; EFSA DRAFT Scientific Opinion on the re-evaluation of aspartame (E 951) as a food additive, 2013) due to early mortality and it was concluded that methanol is not likely to be carcinogenic in humans. Furthermore, the effective doses were above 500 mg/kg/day which is about 35 g/person and day. An acute oral dose level of this magnitude would saturate the folate-dependent metabolism of formic acid to CO2 and be close to a lethal level. Upon inhalation over several hours such a dose, equivalent to an air concentration of 3500 mg/m3, would have to be associated with eye irritation, blurred vision and nausea (Greim, H., 2001).The EU OEL and proposed DNEL is 13-fold lower.