3-methylpentane

H225: Highly Flammable liquid and vapor [Danger Flammable liquids]

H304: May be fatal if swallowed and enters airways [Danger Aspiration hazard]

H315: Causes skin irritation [Warning Skin corrosion/irritation]

H336: May cause drowsiness or dizziness [Warning Specific target organ toxicity, single exposure; Narcotic effects]

H411: Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

P210, P233, P240, P241, P242, P243, P261, P264, P271, P273, P280, P301+P316, P302+P352, P303+P361+P353, P304+P340, P319, P321, P331, P332+P317, P362+P364, P370+P378, P391, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

H225 (100%): Highly Flammable liquid and vapor [Danger Flammable liquids]

H304 (99.7%): May be fatal if swallowed and enters airways [Danger Aspiration hazard]

H315 (99.1%): Causes skin irritation [Warning Skin corrosion/irritation]

H319 (11.4%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H336 (93.5%): May cause drowsiness or dizziness [Warning Specific target organ toxicity, single exposure; Narcotic effects]

H411 (93%): Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

P210, P233, P240, P241, P242, P243, P261, P264, P264+P265, P271, P273, P280, P301+P316, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P319, P321, P331, P332+P317, P337+P317, P362+P364, P370+P378, P391, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 341 reports by companies from 26 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

Fresh air, rest.

Remove contaminated clothes. Rinse and then wash skin with water and soap.

First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.

Rinse mouth. Give nothing to drink. Do NOT induce vomiting. Refer immediately for medical attention.

Use alcohol-resistant foam, powder, carbon dioxide, water. In case of fire: keep drums, etc., cool by spraying with water.

Powder, aqueous film-forming foam (AFFF), foam, carbon dioxide ... keep drums, etc, cool by spraying with water.

WATER MAY BE INEFFECTIVE.

The vapor is heavier than air and may travel along the ground; distant ignition possible. As a result of flow, agitation, etc, electrostatic charges can be generated ... A harmful contamination of the air can be reached rather quickly on evaporation of this substance at 20 °C.

Evacuate danger area! Consult an expert! Personal protection: filter respirator for organic gases and vapours of low boiling point adapted to the airborne concentration of the substance. Remove all ignition sources. Ventilation. Do NOT wash away into sewer. Do NOT let this chemical enter the environment. Collect leaking and spilled liquid in sealable non-plastic containers as far as possible. Absorb remaining liquid in sand or inert absorbent. Wash away remainder with plenty of water. Then store and dispose of according to local regulations.

Ventilation. Collect leaking liquid in sealable containers. Absorb remaining liquid in sand or inert absorbent and remove to safe place. Do NOT wash away into sewer.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

NO open flames, NO sparks, and NO smoking ... Closed system, ventilation, explosion-proof electrical equipment and lighting. Prevent build-up of electrostatic charges (eg, by grounding). Do NOT use compressed air for filling, discharging, or handling ... Do not eat, drink, or smoke during work.

SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants.

Remove contaminated clothes. Rinse and then wash skin with water and soap ... /For eyes:/ First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then take to a doctor.

Fireproof. Cooled. Separated from strong oxidants. Store in an area without drain or sewer access. Do NOT store or transport in containers made from plastic.

Fireproof. Separated from strong oxidants.

500.0 [ppm]

1000 [ppm]

11000 [ppm]

66000 [ppm]

100 ppm (350 mg/m³)

510 ppm (1800 mg/m³) [15 minutes]

200.0 [ppm]

500 ppm as TWA; 1000 ppm as STEL.

500 ppm [1979]

1000 ppm [1979]

1800 mg/m

Chronic Inhalation: 0.6 ppm (L134)

A harmful contamination of the air can be reached rather quickly on evaporation of this substance at 20 °C.

The substance and the vapour are mildly irritating to the eyes, respiratory tract and skin. If swallowed the substance easily enters the airways and could result in aspiration pneumonitis. The substance may cause effects on nervous system. This may result in lowering of consciousness.

The substance defats the skin, which may cause dryness or cracking. Repeated or prolonged contact with skin may cause dermatitis.

... Breathing protection ... Protective gloves ... Safety spectacles ...

NO open flames, NO sparks and NO smoking. Closed system, ventilation, explosion-proof electrical equipment and lighting. Prevent build-up of electrostatic charges (e.g., by grounding). Do NOT use compressed air for filling, discharging, or handling.

Use ventilation, local exhaust or breathing protection.

Protective gloves.

Wear safety goggles.

Do not eat, drink, or smoke during work.

Colorless liquid; [Hawley]

COLOURLESS LIQUID WITH CHARACTERISTIC ODOUR.

Clear liquids with mild, gasoline-like odors.

Colorless liquid

63.271 °C

63.3 °C @760 [mm Hg]

-162.9 °C

-245 to -148 °F

<20 °F (< -7 °C) (Closed cup)

-54 to 19 °F

Sol in ethanol, carbon tetrachloride; miscible in ether, acetone, benzene, heptane

In water, 17.9 mg/L at 25 °C

Solubility in water: none

0.66431 g/cu cm at 20 °C; 0.65976 g/cu cm at 25 °C

Liquid density = 664.31 kg/cu m at 20 °C

Relative density (water = 1): 0.66

0.65-0.66

0.69576 @25 °C

3.0 (AIR= 1)

Relative vapor density (air = 1): 2.97

190.0 [mmHg]

190 mm Hg at 25 °C

Vapor pressure, kPa at 20 °C: 20.5

190 [mm Hg] @25 °C

log Kow = 3.60

3.6 (estimated)

532 °F (278 °C)

0.3031 cP at 19.986 °C; 0.307 cP at 25 °C

-994.14 kcal/mol at 25 °C

7.236 kcal/mol at 25 °C

18.12 dynes/cm at 20 °C; 17.60 dynes/cm at 25 °C

Index of refraction = 1.37652 at 20 °C; 1.37386 at 25 °C

Triple point = -162.898 °C

Heat of fusion = -48.37 kcal/mol at 25 °C

Heat capacity at constant pressure = 33.49 cal/K-mol at 25 °C

Dielectric constant: 1.895

For more Other Experimental Properties (Complete) data for 3-METHYLPENTANE (6 total), please visit the HSDB record page.

Boiling point

Chemical diffusion

Composition

Reacts violently with oxidants causing fire and explosion hazard. Attacks plastic.

...Can react vigorously with oxidizing materials.

Hexane's toxicity is caused by it neurotoxic metabolite, 2,5-hexanedione. It damages the central and peripheral nervous system by causing axonal swelling and degeneration. 2,5-Hexanedione also reacts with lysine side-chain amino groups in axonal cytoskeletal proteins to form pyrroles. This results in neurofilament cross-linking and loss of function. (L175)

No indication of carcinogenicity to humans (not listed by IARC).

Hexane mainly affects the nervous system. It causes degeneration of the peripheral nervous system (and eventually the central nervous system), starting with damage to the nerve axons. Exposure to hexane may also damage the lungs and reproductive system. (L977, L978)

The substance can be absorbed into the body by inhalation of its vapour.

Oral (L175) ;inhalation (L175) ;dermal (L175)

Cough. Headache. Dizziness. Unconsciousness.

Redness.

Redness. Pain.

Aspiration hazard! Abdominal pain. Nausea. Vomiting. Diarrhoea. Further see Inhalation.

Breathing large amounts of hexane causes numbness in the feet and hands, followed by muscle weakness in the feet and lower legs. Continued exposure may lead to paralysis of the arms and legs. However, if removed from the exposure, recovery occurs in 6 months to a year. Inhalation of high concentrations produces first a state of mild euphoria, followed by somnolence with headaches and nausea. (L175, A121)

Neurotoxin - Acute solvent syndrome

ACGIH Carcinogen - Confirmed Animal.

Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool. Administer activated charcoal ... . Treat frostbite with rapid rewarming techniques ... ./Aliphatic hydrocarbons and related compounds/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag-valve-mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously.Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Aliphatic hydrocarbons and related compounds/

Objectives: To investigate the possibilities of personal ambient monitoring and biological monitoring for methylpentane isomers. Methods: The performance of activated carbon cloth to absorb 2- and 3-methylpentane was studied by experimental vapor exposure followed by solvent extraction and gas chromatography. Urine from workers and rats exposed to 2- and 3-methylpentane was analysed by gas chromatography with or without acid or enzymatic hydrolysis. Results: Carbon cloth absorbed 2- and 3-methylpentane linearly to exposures up to eight hours and to 400 ppm, and was sensitive enough to detect a 15 minute peak of exposure. The two isomers were clearly separated from hexane on a DB-l column. For analysis of the urine, enzymatic hydrolysis was superior to acid hydrolysis. Exposure of rats to methylpentane vapors showed that 2-methyl-2-pentanol and 3-methyl-2-pentanol were excreted in urine in proportion to the dose of 2-methylpentane and 3-methylpentane, respectively. 2-Methyl derivatives of 1-, 3-, and 4-propanol, 2-methylpentane-2,4-diol, and 3-methyl-2-pentanol were minor metabolites. Analysis of urine from the exposed workers showed that 2-methyl and 3-methyl-2-pentanol are leading urinary metabolites after exposure to the corresponding methylpentane. Conclusions: Diffusive sampling is applicable to monitor 2- and 3-methylpentane vapors as is the case for hexane vapor. 2-Methyl-2-pentanol and 3-methyl-2-pentanol will be markers of occupational exposure to 2-methylpentane and 3-methylpentane, respectively. Also, 2-methylpentane-2,4-diol might be a marker of exposure to 2-methylpentane.

/EPIDEMIOLOGY STUDIES/ A high risk of spontaneous abortion was observed in women exposed to organic solvents during pregnancy. Since this risk was not found in the shoe industry, where these solvents are widely used, we carried out a case-control study on the risk of spontaneous abortion in a health district (Veneto, Northern Italy) where about 8,000 people work in shoe manufacturing. Aliphatic hydrocarbons were generally used; their concentrations were repeatedly below the mixture TLVs in the observation period. Methods: Cases (clinically recognized spontaneous abortion, ICD codes 632-634-636) and age-/year-/residence-matched controls (admitted for normal delivery) were traced in the files of the regional hospital discharges register. Data on 108 cases (81% response) and the same number of reference subjects were collected on questionnaires completed by nurses trained in occupational medicine. There were questions on confounding and occupational factors, and an open question to ensure a complete description of work done during pregnancy. An occupational physician, working blind, then coded exposure to organic solvents according to a three-level polytomous variable (no, low, high exposure). The cases/controls not exposed, exposed to low levels and exposed to high levels of organic solvents were 78/88, 12/12, and 18/8 respectively. Adjusted for the confounding factors, the relative risk (RR) of spontaneous abortion for high exposure to organic solvents during pregnancy was 3.85, with 95% confidence intervals (CI) ranging from 1.24 to 11.9. RR was 1.58 (CI = 0.62-4.06) in women exposed to low solvent concentrations. Our results support the hypothesis that spontaneous abortion may be an adverse effect of exposure to high levels of organic aliphatic solvents in women employed in shoe manufacture.

/BIOMONITORING/ Multiple chemical sensitivity (MCS), although poorly understood, is associated with considerable morbidity. AIM: To investigate potential biological mechanisms underlying MCS in a case-control study. Two hundred and twenty-three MCS cases and 194 controls (urban females, aged 30-64 years) fulfilled reproducible eligibility criteria with discriminant validity. Routine laboratory results and serum levels of volatile organic compounds (VOCs) were compared. Dose-response relationships, a criterion for causality, were examined linking exposures to likelihood of case status. Routine laboratory investigations revealed clinically unimportant case-control differences in means. Confounder-adjusted odds ratios (OR) showed MCS was negatively associated with lymphocyte count and total plasma homocysteine, positively associated with mean cell hemoglobin concentration, alanine aminotransferase and serum vitamin B6, and not associated with thyroid stimulating hormone, folate or serum vitamin B12. More cases than controls had detectable serum chloroform (P = 0.001) with the OR for detectability 2.78 (95% confidence interval = 1.73-4.48, P < 0.001). Chloroform levels were higher in cases. However, cases had significantly lower means of detectable serum levels of ethylbenzene, m&p-xylene, 3-methylpentane and hexane, and means of all serum levels of 1,3,5- and 1,2,3-trimethylbenzene, 2- and 3-methylpentane, and m&p-xylene. Our findings are inconsistent with proposals that MCS is associated with vitamin deficiency or thyroid dysfunction, but the association of lower lymphocyte counts with an increased likelihood of MCS is consistent with theories of immune dysfunction in MCS. Whether avoidance of exposures or different metabolic pathways in cases explain the observed lower VOC levels or the higher chloroform levels should be investigated.

/BIOMONITORING/ 3-Methyl-2-pentanol may be measured by GC in urine as a biomarker of occupational exposure to 3-methylpentane.

/BIOMONITORING/ Ten different solvents, viz., toluene, styrene, methylethyl ketone, acetone, dimethylformamide, cyclohexane, n-hexane, methylcyclopentane, 2-methylpentane, and 3-methylpentane were determined in environmental air and in the alveolar air of workers during the work shift. As regards all ten solvents studied, alveolar concentration (Ca) and the difference between environmental concentration (Ci) and alveolar concentration (Ci-Ca), were correlated with environmental concentration. According to the slopes of the regression lines, the ratio between alveolar and environmental concentration (Ca/Ci) and the alveolar retention ((Ci-Ca)/Ci) in the case of all ten solvents studied were complementary, i.e., their sum was equal to unity. The solvents with high solubility in blood, i.e., toluene, styrene, methylethyl ketone, acetone, and dimethylformamide showed a Ca/Ci ratio lower than 0.5 and the solvents with low solubility, i.e., cyclohexane, hexane, and their isomers showed a Ca/Ci ratio higher than 0.5. According to the findings which prove that the alveolar concentration of all solvents studied during the work shift is a function of variations in the environmental concentrations it seems reasonable to suggest the use of alveolar tests for monitoring environmental exposure to solvents during the work shift.

/LABORATORY ANIMALS: Neurotoxicity/ Rats were intermittently exposed (9 to 10 hr/day, 5 to 6 days/week ) to controlled concentrations of single analytical grade solvents in ambient air. After periods ranging from 7 to 30 weeks the animals were perfused with glutaraldehyde and samples of nerves were processed for light microscopy of sections and of teased fibers. Animals treated with n-hexane at 5000 ppm (14 weeks) or 2500 ppm, (30 weeks) developed the typical giant axonal degeneration already described in rats treated continuously with 400 to 600 ppm of the same solvent for 7 weeks or more. No such alterations were found in rats subjected to the following intermittent respiratory treatments: n-hexane 500 ppm (30 weeks), or 1500 ppm (14 weeks), cyclohexane 1500 or 2500 (30 weeks), n-pentane 3000 ppm (30 weeks), n-heptane 1500 ppm (30 weeks), 2-methylpentane 1500 ppm (14 weeks), and 3-methylpentane 1500 ppm (14 weeks). The following metabolites were found in the urine of rats according to treatment (in parenthesis): 2-methyl-2-pentanol (2-methylpentane); 3-methyl-2-pentanol and 3-methyl-3-pentanol (3-methylpentane), 2-hexanol, 3-hexanol, gamma-valerolactone, 2,5-dimethylfuran, and 2,5-hexanedione (n-hexane). 2-Hexanol was found to be the main urinary metabolite of n-hexane, while 2,5-hexanedione was present only in a lesser proportion. This feature of rat metabolism suggests that in this species 2,5-hexanedione reaches an effective level at its site of action during intermittent respiratory treatment with n-hexane with difficulty and explains the high concentrations necessary to cause polyneuropathy in rats subjected to this treatment.[Frontali N et al; Clin Toxicol 18 (12): 1357-67 (1981)]

/GENOTOXICITY/ The cytogenetic effects of commercial hexane solvent were investigated. Commercial hexane solvent contained several 6-carbon isomers including mostly n-hexane, 3-methylpentane, methylcyclopentane, and 2-methylpentane. Both in-vitro and in-vivo tests were conducted. Chinese-hamster-ovary cells were exposed to nine concentrations of commercial hexane solvents ranging from 5.0 x 10-4 to 5.0 uL/mL. At completion of a 6 hr exposure cells were washed with buffered saline containing bromodeoxyuridine for 20 hr. The mitotic index was determined, and chromosome aberrations were sought in Giemsa stained preparation. Sprague-Dawley-rats of both sexes were exposed, nose only, to 6 hr of commercial hexane solvent at target concentrations of 900, 3,000, and 9,000 ppm. Rats were sacrificed at 6 hr and 24 hr postexposure (colchicine being administered 2 hr prior to sacrifice by intraperitoneal injection). Bone marrow cells were obtained and examined after Giemsa staining. Results of the commercial hexane solvent cell screening test showed that the highest doses tested produced overt cellular toxicity and corresponding reductions in mitotic indices. Cell cycle kinetics was delayed at these levels. In the absence of S9 activation cell toxicity was evident at the three highest commercial hexane solvent concentrations. However, no chromosome alterations were evident in any group tested. In the in-vivo assay increased lacrimation was the only overt sign of toxicity. The cytogenetic analysis showed no increase in chromosomal damage irrespective of concentration bone marrow collection time or sex of the animal. /It was/ concluded that the mixture of 6-carbon isomers comprising commercial hexane solvent does not have any significant genotoxic activity.[Daughtrey WC et al; Journal of Applied Toxicology 14 (3): 161-165 (1994)]

The potential neurotoxicity of n-hexane mixtures was evaluated in groups of 4 young adult male rats exposed by whole-body inhalation for 22 hours/day, 7 days/week, for periods up to 6 months. Test mixtures consisted of the following ratios (expressed as ppm) of n-hexane isomers that contained six carbon atoms free of n-hexane: 0/0; 125/0, 125/125; 125/375; 125/1375; 500/0. Neuropathy of central and peripheral nervous system fibers (giant axonal swellings containing accumulated neurofilaments) was seen only in the 500/0 ppm mixture. A 2nd phase of the study was conducted in male rats similarly exposed to hexane concentrations of 0, 500 ppm n-hexane-free hexanes (mixed hexanes) (Group II), 500 ppm n-hexane/500 ppm mixed hexanes (Group III), or 500 ppm n-hexane (Group IV). Abnormal gait and decreased body weight were observed in Group III and IV animals, along with trace to mild atrophy of sciatic and/or anterior tibial nerves. Nerve and muscle lesions were not evident in rats treated with 500 ppm of mixed hexanes. Renal lesions and increased mean absolute and/or relative weight of kidneys were seen in all treatment groups.[EPA/OTS; Doc #40-8223010]

The substance is toxic to aquatic organisms. It is strongly advised not to let the chemical enter into the environment.

3-Methylpentane's production and use as solvent, raw material, fuel, and lubricant may result in its release to the environment through various waste streams. Natural sources of 3-methylpentane include petroleum, natural gas, ocean water, and underwater hydrocarbon vents. If released to air, a vapor pressure of 190 mm Hg at 25 °C indicates 3-methylpentane will exist solely as a vapor in the atmosphere. Vapor-phase 3-methylpentane will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 28 days. 3-Methylpentane does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight. If released to soil, 3-methylpentane is expected to have slight mobility based upon an estimated Koc of 2200. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 1.7 atm-cu m/mole. However, adsorption to soil is expected to attenuate volatilization. 3-Methylpentane may volatilize from dry soil surfaces based upon its vapor pressure. 3-Methylpentane degraded 100% after 30 days in activated sludge during a closed-bottle test, but an acclimation period of 27.4 days was observed. Therefore, biodegradation in soil and water is expected to be an important fate process, however volatilization is expected to be the dominant fate process. If released into water, 3-methylpentane is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 57 minutes and 3.7 days, respectively. However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. An estimated BCF of 131 suggests the potential for bioconcentration in aquatic organisms is high. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions. Occupational exposure to 3-methylpentane may occur through inhalation and dermal contact with this compound at workplaces where 3-methylpentane is produced or used. Monitoring data indicate that the general population may be exposed to 3-methylpentane via inhalation of ambient air with this compound and from other consumer products containing 3-methylpentane. 3-Methylpentane was widely detected in air samples taken from roadway tunnels and urban centers. Studies indicate that transportation exhaust is the major source of 3-methylpentane concentration in air. (SRC)

3-Methylpentane naturally occurs in petroleum and natural gas(1). It is also a plant volatile(1). From its Henry's Law constant and atmospheric concns over the ocean, oceans appear to be supersaturated with 3-methylpentane by 2-3 orders of magnitude indicating that they are a source of 3-methylpentane(2). However, oceans are a minor source of alkanes compared with continental production(2). None of the emission of 12 trees in Louisianna tested contained 3-methylpentane(4).

3-Methylpentane's production and use as a solvent, in organic synthesis(1), a raw material for carbon black, a fuel and lubricant (in mixture with other saturated hydrocarbons)(2), in the manufacture of polyolefins, synthetic rubbers, and some pharmaceuticals may result in its release to the environment through various waste streams(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 2,200(SRC), determined from a log Kow of 3.60(2) and a regression-derived equation(3), indicates that 3-methylpentane is expected to have slight mobility in soil(SRC). Volatilization of 3-methylpentane from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.7 atm-cu m/mole(SRC), derived from its vapor pressure, 190 mm Hg(4), and water solubility, 17.9 mg/L(5). 3-Methylpentane is expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(4). However, adsorption to soil is expected to attenuate volatilization(SRC). 3-Methylpentane biodegraded 100% after 30 days using an activated sludge inoculum but following 27.4 days acclimation(6), indicating that biodegradation is expected to be an important fate process in soil(SRC). However, volatilization is expected to be the dominant fate process(SRC).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 2,200(SRC), determined from a log Kow of 3.60(2) and a regression-derived equation(3), indicates that 3-methylpentane is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 1.7 atm-cu m/mole(SRC)derived from its vapor pressure, 190 mm Hg(4), and water solubility, 17.9 mg/L(5). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 57 min and 3.7 days, respectively(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 11 days if adsorption is considered(6). According to a classification scheme(7), an estimated BCF of 320(SRC), from an estimated log Kow of 3.6(8) and a regression-derived equation(9), suggests the potential for bioconcentration in aquatic organisms is high(SRC). 3-Methylpentane biodegraded 100% after 30 days using an activated sludge inoculum but following 27.4 days acclimation(10), indicating that biodegradation is expected to be an important fate process in water(SRC). However, volatilization is expected to be the dominant fate process(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 3-methylpentane, which has a vapor pressure of 190 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 3-methylpentane is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 28 days(SRC), calculated from its rate constant of 5.7X10-12 cu cm/molecule-sec at 25 °C(3). 3-Methylpentane does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight(4).

AEROBIC: 3-Methylpentane, present at 19.3 mg/L in a light fraction of gasoline, exhibited 100% CO2 evolution after 30 days in an 100 mg/L activated sludge inoculum and 16% CO2 evolution after 30 days in an abiotic control during a closed-flask test(1). Technical 3-methylpentane test sample and an abiotic control, under the same test conditions, exhibited CO2 production of 100% and 18%, respectively, after 30 days(1). 3-Methylpentane was observed to have a lag period of 27.4 days and a degradation rate of 66 umol/hr(1). A final mineralization yield of 31% was calculated(1). Based on this data, biodegradation of 3-methylpentane in the environment is expected to be an important fate process, however volatilization is expected to be the dominant fate process(SRC).

AEROBIC: Indigenous soil microorganisms will biodegrade petroleum products under aerobic conditions(1,2). None of the 32 cutures isolated from groundwater after a spill that were tested for their ability to biodegrade components of gasoline grew on 3-methylpentane(3). However, 7% of 3-methylpentane biodegraded in 8 days when incubated with a groundwater contaminated with gasoline(3). Therefore cooxidation may play an important role in the biodegradation of 3-methylpentane(3).

ANAEROBIC: Biodegradation of 3-methylpentane can occur under anaerobic conditions at much slower rates than under aerobic conditions, particularly by sulfur-reducing bacteria(1).

The rate constant for the vapor-phase reaction of 3-methylpentane with photochemically-produced hydroxyl radicals is 5.7X10-12 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 28 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(2). 3-Methylpentane is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(3). 3-Methylpentane does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight(3). The observed seasonal variation in year-long monitoring at four rural sites across Canada is consistent with increased photochemical destruction of 3-methylpentane during the summer(4).

An estimated BCF of 320 was calculated for 3-methylpentane(SRC), using a log Kow of 3.6(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is high(SRC), provided the compound is not metabolized by the organism(SRC).

The Koc of 3-methylpentane is estimated as 2,200(SRC), using a log Kow of 3.60(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that 3-methylpentane is expected to have slight mobility in soil.

The Henry's Law constant for 3-methylpentane is estimated as 1.7 atm-cu m/mole(SRC) derived from its vapor pressure, 190 mm Hg(1), and water solubility, 17.9 mg/L(2). This Henry's Law constant indicates that 3-methylpentane is expected to volatilize rapidly from water surfaces(3). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(3) is estimated as 57 minutes(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(3) is estimated as 3.7 days(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 11 days if adsorption is considered(4). 3-Methylpentane's estimated Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). The potential for volatilization of 3-methylpentane from dry soil surfaces may exist(SRC) based upon its vapor pressure(1).

DRINKING WATER: 3-Methylpentane was present in the one sample of tap water analyzed in New Jersey as part of the USEPA Total Exposure Assessment Methodology (TEAM) study(1).

SURFACE WATER: The concn of 3-methylpentane in surface water in the Indian Ocean (n=8) ranged from 0.09 to 2.15 nL/L(1). While the concn varied, the relative abundance of 3-methylpentane with respect to nonmethane hydrocarbons was practically constant(1).

In a comprehensive survey of wastewater from 4000 industrial and publicly owned treatment works (POTWs) sponsored by the Effluent Guidelines Division of the USEPA, 3-methylpentane was identified in discharges of the following industrial category (positive occurrences, median concn in ppb): petroleum refining (5; 27.7), organics and plastics (15; 74.4), inorganic chemicals (1; 112.6), plastics and synthetics (6; 64.1), rubber processing (1; 9.6), pharmaceuticals (2; 895.4), publicly owned treatment works (19; 2.2)(1). The highest effluent concn was 1769 ppb in the pharmaceuticals industry(1).

The 3-methylpentane content of gasoline-related substances in wt %: gasoline exhaust (noncatalyzed), 1.1%; gasoline exhaust (catalyzed), 1.3%; unburned gas, 2.1%; headspace vapors, 1.6%(1). The average exhaust in Sydney, Australia had a 3-methylpentane concn of 0.17 ppbC which was 1.6 wt% of NMHC(2). 3-Methylpentane constituted 2.5-3.1 wt% of non-methane hydrocarbons (NMHC) in a Swedish tunnel(3), 2.8 wt% in a tunnel in Budapest, Hungary(4).

The substance is toxic to aquatic organisms. It is strongly advised not to let the chemical enter into the environment.

3-Methylpentane's production and use as solvent, raw material, fuel, and lubricant may result in its release to the environment through various waste streams. Natural sources of 3-methylpentane include petroleum, natural gas, ocean water, and underwater hydrocarbon vents. If released to air, a vapor pressure of 190 mm Hg at 25 °C indicates 3-methylpentane will exist solely as a vapor in the atmosphere. Vapor-phase 3-methylpentane will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 28 days. 3-Methylpentane does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight. If released to soil, 3-methylpentane is expected to have slight mobility based upon an estimated Koc of 2200. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 1.7 atm-cu m/mole. However, adsorption to soil is expected to attenuate volatilization. 3-Methylpentane may volatilize from dry soil surfaces based upon its vapor pressure. 3-Methylpentane degraded 100% after 30 days in activated sludge during a closed-bottle test, but an acclimation period of 27.4 days was observed. Therefore, biodegradation in soil and water is expected to be an important fate process, however volatilization is expected to be the dominant fate process. If released into water, 3-methylpentane is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is expected to be an important fate process based upon this compound's estimated Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 57 minutes and 3.7 days, respectively. However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. An estimated BCF of 131 suggests the potential for bioconcentration in aquatic organisms is high. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions. Occupational exposure to 3-methylpentane may occur through inhalation and dermal contact with this compound at workplaces where 3-methylpentane is produced or used. Monitoring data indicate that the general population may be exposed to 3-methylpentane via inhalation of ambient air with this compound and from other consumer products containing 3-methylpentane. 3-Methylpentane was widely detected in air samples taken from roadway tunnels and urban centers. Studies indicate that transportation exhaust is the major source of 3-methylpentane concentration in air. (SRC)

3-Methylpentane naturally occurs in petroleum and natural gas(1). It is also a plant volatile(1). From its Henry's Law constant and atmospheric concns over the ocean, oceans appear to be supersaturated with 3-methylpentane by 2-3 orders of magnitude indicating that they are a source of 3-methylpentane(2). However, oceans are a minor source of alkanes compared with continental production(2). None of the emission of 12 trees in Louisianna tested contained 3-methylpentane(4).

3-Methylpentane's production and use as a solvent, in organic synthesis(1), a raw material for carbon black, a fuel and lubricant (in mixture with other saturated hydrocarbons)(2), in the manufacture of polyolefins, synthetic rubbers, and some pharmaceuticals may result in its release to the environment through various waste streams(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 2,200(SRC), determined from a log Kow of 3.60(2) and a regression-derived equation(3), indicates that 3-methylpentane is expected to have slight mobility in soil(SRC). Volatilization of 3-methylpentane from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.7 atm-cu m/mole(SRC), derived from its vapor pressure, 190 mm Hg(4), and water solubility, 17.9 mg/L(5). 3-Methylpentane is expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(4). However, adsorption to soil is expected to attenuate volatilization(SRC). 3-Methylpentane biodegraded 100% after 30 days using an activated sludge inoculum but following 27.4 days acclimation(6), indicating that biodegradation is expected to be an important fate process in soil(SRC). However, volatilization is expected to be the dominant fate process(SRC).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 2,200(SRC), determined from a log Kow of 3.60(2) and a regression-derived equation(3), indicates that 3-methylpentane is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(3) based upon an estimated Henry's Law constant of 1.7 atm-cu m/mole(SRC)derived from its vapor pressure, 190 mm Hg(4), and water solubility, 17.9 mg/L(5). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 57 min and 3.7 days, respectively(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 11 days if adsorption is considered(6). According to a classification scheme(7), an estimated BCF of 320(SRC), from an estimated log Kow of 3.6(8) and a regression-derived equation(9), suggests the potential for bioconcentration in aquatic organisms is high(SRC). 3-Methylpentane biodegraded 100% after 30 days using an activated sludge inoculum but following 27.4 days acclimation(10), indicating that biodegradation is expected to be an important fate process in water(SRC). However, volatilization is expected to be the dominant fate process(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 3-methylpentane, which has a vapor pressure of 190 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 3-methylpentane is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 28 days(SRC), calculated from its rate constant of 5.7X10-12 cu cm/molecule-sec at 25 °C(3). 3-Methylpentane does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight(4).

AEROBIC: 3-Methylpentane, present at 19.3 mg/L in a light fraction of gasoline, exhibited 100% CO2 evolution after 30 days in an 100 mg/L activated sludge inoculum and 16% CO2 evolution after 30 days in an abiotic control during a closed-flask test(1). Technical 3-methylpentane test sample and an abiotic control, under the same test conditions, exhibited CO2 production of 100% and 18%, respectively, after 30 days(1). 3-Methylpentane was observed to have a lag period of 27.4 days and a degradation rate of 66 umol/hr(1). A final mineralization yield of 31% was calculated(1). Based on this data, biodegradation of 3-methylpentane in the environment is expected to be an important fate process, however volatilization is expected to be the dominant fate process(SRC).

AEROBIC: Indigenous soil microorganisms will biodegrade petroleum products under aerobic conditions(1,2). None of the 32 cutures isolated from groundwater after a spill that were tested for their ability to biodegrade components of gasoline grew on 3-methylpentane(3). However, 7% of 3-methylpentane biodegraded in 8 days when incubated with a groundwater contaminated with gasoline(3). Therefore cooxidation may play an important role in the biodegradation of 3-methylpentane(3).

ANAEROBIC: Biodegradation of 3-methylpentane can occur under anaerobic conditions at much slower rates than under aerobic conditions, particularly by sulfur-reducing bacteria(1).

The rate constant for the vapor-phase reaction of 3-methylpentane with photochemically-produced hydroxyl radicals is 5.7X10-12 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 28 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(2). 3-Methylpentane is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(3). 3-Methylpentane does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight(3). The observed seasonal variation in year-long monitoring at four rural sites across Canada is consistent with increased photochemical destruction of 3-methylpentane during the summer(4).

An estimated BCF of 320 was calculated for 3-methylpentane(SRC), using a log Kow of 3.6(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is high(SRC), provided the compound is not metabolized by the organism(SRC).

The Koc of 3-methylpentane is estimated as 2,200(SRC), using a log Kow of 3.60(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that 3-methylpentane is expected to have slight mobility in soil.

The Henry's Law constant for 3-methylpentane is estimated as 1.7 atm-cu m/mole(SRC) derived from its vapor pressure, 190 mm Hg(1), and water solubility, 17.9 mg/L(2). This Henry's Law constant indicates that 3-methylpentane is expected to volatilize rapidly from water surfaces(3). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(3) is estimated as 57 minutes(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(3) is estimated as 3.7 days(SRC). However, volatilization from water surfaces is expected to be attenuated by adsorption to suspended solids and sediment in the water column. The estimated volatilization half-life from a model pond is 11 days if adsorption is considered(4). 3-Methylpentane's estimated Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). The potential for volatilization of 3-methylpentane from dry soil surfaces may exist(SRC) based upon its vapor pressure(1).

DRINKING WATER: 3-Methylpentane was present in the one sample of tap water analyzed in New Jersey as part of the USEPA Total Exposure Assessment Methodology (TEAM) study(1).

SURFACE WATER: The concn of 3-methylpentane in surface water in the Indian Ocean (n=8) ranged from 0.09 to 2.15 nL/L(1). While the concn varied, the relative abundance of 3-methylpentane with respect to nonmethane hydrocarbons was practically constant(1).

In a comprehensive survey of wastewater from 4000 industrial and publicly owned treatment works (POTWs) sponsored by the Effluent Guidelines Division of the USEPA, 3-methylpentane was identified in discharges of the following industrial category (positive occurrences, median concn in ppb): petroleum refining (5; 27.7), organics and plastics (15; 74.4), inorganic chemicals (1; 112.6), plastics and synthetics (6; 64.1), rubber processing (1; 9.6), pharmaceuticals (2; 895.4), publicly owned treatment works (19; 2.2)(1). The highest effluent concn was 1769 ppb in the pharmaceuticals industry(1).

The 3-methylpentane content of gasoline-related substances in wt %: gasoline exhaust (noncatalyzed), 1.1%; gasoline exhaust (catalyzed), 1.3%; unburned gas, 2.1%; headspace vapors, 1.6%(1). The average exhaust in Sydney, Australia had a 3-methylpentane concn of 0.17 ppbC which was 1.6 wt% of NMHC(2). 3-Methylpentane constituted 2.5-3.1 wt% of non-methane hydrocarbons (NMHC) in a Swedish tunnel(3), 2.8 wt% in a tunnel in Budapest, Hungary(4).

URBAN/SUBURBAN: 39 U.S. Cities between 1984-1986 (n=831) in ppbC: median 10.7, 25th percentile 6.4, 75th percentile 16.6 min 0.1, max 351(1). The mean concn of 3-methylpentane between 6 am and 9 am in 7 US cities: Houston TX, 15 ppbC; Philadelphia PA, 11 ppbC; Baltimore MD, 9 ppbC; Washington DC, 7 ppbC; Newark NJ, 9 ppbC; Boston MA, 8 ppbC; Milwaukee WI, 5 ppbC(2). In the Houston Photooxidant Study, a site downwind from industry and away from local sources was monitored in the summer of 1977; the results for 3-methylpentane (n=684) were 14 ppbC av, 118 ppbC, max(3). The site had a very high ozone concn(3). 3-Methylpentane was present in 50-85% of samples in the urban baseline VOC program in which measurements where made in Washington, DC for 1 year(4). The mean concn at 3 sites in Sydney, Australia over 10 months (n=140) was 1.6 ppb(5). The concn of 3-methylpentane at sites in Vienna, Austria were (site description (number of samples), concn (standard deviation)); urban - top of building 52 m (n=17), 8.0 (5.1) ppbC; urban street with traffic 1.5 m above ground (n=12), 16.1 (15.5) ppbC; suburbs (n=16), 4.5 (4.1) ppbC; local background site (n=9), 2.5 (3.8) ppbC(6). Bangkok, Thailand 15-20 ug/cu m in inner city, 8 ug/cu m at dump on edge of city, 1-2 ug/cu m in community on edge of city(7). Ambient air concns for 3-methylpentane in the National Ambient Volatile Organic Compounds data base (n = 867): mean 2.550 ppb, median 1.525 ppb, 25th percentile 0.845 ppb, 75th percentile 2.633 ppb(8). The median concn by type of site were (type, number of data points, concn): suburban, 220 1.567 ppb; urban, 534, 1.635 ppb(8). Monitoring studies conducted in May-July 1983 in northwest England at different types of sites (n=22) (type, mean, (standard deviation)): urban, 40.2 (20.8) ppbC(9).

URBAN/SUBURBAN: 3-Methylpentane was detected at concns ranging from 0.9-4.7 ppbV and averaging 2.3 ppbV from samples collected from Ancient Angora, Athens, Greece 4 m above ground between June 9-12 of 1993, May 6-7 and 9-10 and July 7-9, 11 of 1994(1). Other studies detecting 3-methylpentane from air samples in urban centers reported concns of 1.9 ppbV in Vienna, 1.6 ppbV in Sydney, 2.4 ppbV in Chicago, 3.1 ppbV in Osaka(1). 3-methylpentane was detected at an average concn of 1.9 ppbV from samples collected in the Shan-Hua, May-Nung, Ping-Tung, Chao-Chou areas of Taiwan during two 5 day periods in December 1998 and May 1999(2).

INDOOR AIR: The maximum indoor and outdoor concn of 3-methylpentane found in 300 Dutch homes was 101 ug/cu m and 3 ug/cu m, respectively(1).

INDOOR: An indoor air review concerning volatile organic compounds reported a weighted arithmetic geometric mean concn of 3-methylpentane in complaint buildings of 21 ug/cu m, 7 times higher than concns in other established buildings(1). The concns of 3-methylpentane inside 3 cars were determined during a suburban commute in NJ and during a commute from NJ into New York City(2). The mean and median concns in ug/cu m found were (trip, mean, median): suburban route-low ventilation (n=10), 4.0, 3.9; suburban route-high ventilation (n=7), 1.5, 2.2; NYC-turnpike commute (n=5), 18, 6.8; NYC-tunnel commute (n=5), 80, 5(2). The suburban route was 23 km with an average exposure time of 23 minutes and the NYC commute, made under low ventilation conditions, was 49 km and 45 minutes on the turnpike and 5 km and 33 minutes in the tunnel(2). The concns of 3-methylpentane in a car and train (n=8) during parallel commuter trips in Goeteborg, Sweden was 10.5 and 2.0 ug/cu m, respectively(3). Traffic emissions have been identified as a major source of 3-methylpentane detected in indoor air of office buildings in Greece(4).

For more Atmospheric Concentrations (Complete) data for 3-METHYLPENTANE (7 total), please visit the HSDB record page.

3-Methylpentane has been identified as a volatile in beef(1) and tree-ripened nectarines(2).

In a 1982 study, the composition of leaded, unleaded, and super unleaded gas was 4.5, 3.4, and 2.4% 3-methylpentane, respectively(1). The Auto/Oil program database reports that the industry average gasoline contains 2.422% 3-methylpentane(2). Composition profiles for 3-methylpentane acquired during the Southern California Air Quality Study in wt% include: commercial natural gas, 0.10; geogenic natural gas, 1.50; liquified petroleum gas, 0.00; diurnal evaporative emissions, 2.00; hot soak evaporative emissions, 2.59; running loss evaporative emissions, 1.30; summer gas, 2.03; winter gas, 1.77; summer gas headspace, 1.56; winter gas headspace, 1.49(3). The 3-methylpentane content (ppbC%) of sources from the 1990 Atlanta Ozone Precursor Monitoring Study were: whole gas (weighted avg all octanes), 1.79; whole gas 87 octane, 2.12; whole gas 89 octane, 1.57; whole gas 92/93 octane, 1.03; headspace gas 24 °C (all octanes), 1.93; headspace gas 32 °C (all octanes), 2.01(4).

The 3-methylpentane content of gasoline-related substances in wt%: gasoline exhaust (noncatalyzed), 1.1%; gasoline exhaust (catalyzed), 1.3%; unburned gas, 2.1%; headspace vapors, 1.6%(1). The 3-methylpentane content (ppbC%) of sources from the 1990 Atlanta Ozone Precursor Monitoring Study were: whole gas (weighted avg all octanes), 1.79; whole gas 87 octane, 2.12; whole gas 89 octane, 1.57; whole gas 92/93 octane, 1.03; headspace gas 24 °C (all octanes), 1.93; headspace gas 32 °C (all octanes), 2.01(2). A similar study yielded 3-methylpentane emission profiles (wt%) in the Chicago area as: regular gas, 2.00; mid-grade gas, 1.33; premium gas 0.77; hot soak emissions, 2.25; cold start emissions, 2.33(3). 3-Methylpentane constituted 0.30 wt% and 2.4 wt% of NMHC in exhaust from mopeds using alkylate and standard reformate fuel, respectively(4). The respective compositions of these fuels were 0.30 and 2.5 wt%(6). The average exhaust in Sydney, Australia had a 3-methylpentane concn of 0.17 ppbC which was 1.6 wt% of NMHC(5).

3-Methylpentane is often found in glue used in shoe manufacturing; of the 43 glues analyzed, 48% contained 3-methylpentane(1). The percent of 3-methylpentane in the glues ranged from 1-35% with a mean and median of 12% and 14%, respectively(1). 3-Methylpentane was not used in the 22 solvents analyzed that were used as glue diluents.

AIR COMPOSITION PROFILES: The 3-methylpentane content (ppbC%) of vehicle-related air samples from the 1990 Atlanta Ozone Precursor Monitoring Study were: roadway (n=9), 1.418, airport (n=11), 0.96; aircraft (n=2), 0.550(1). The roadway samples were collected along a busy interstate during morning rush hour in August. Other roadway emission profiles for 3-methylpentane in wt% are: Chicago, 1.69(2); Lincoln Tunnel, 1.72(2,4); Atlanta roadway, 1.56(2); Caldecott Tunnel, San Francisco, CA (6/26-8/1991) 1.85%, mean(5). The Chicago profiles were taken on a confined parkway during rush hour traffic. 3-Methylpentane constituted 2.5-3.1 wt% of non-methane hydrocarbons (NMHC) in a Swedish tunnel(6), 2.8 wt% in a tunnel in Budapest, Hungary(7). Tunnel emission are composed of evaporative losses and exhaust(7). The ground level emissions 1 mi downwind from a refinery contained 0.88-1.48 wt%, mean 1.21 wt% 3-methylpentane(2). An earlier study reported 1.27-9.36 wt%, mean 3.42(3).

Occupational exposure to 3-methylpentane may occur through inhalation and dermal contact with this compound at workplaces where 3-methylpentane is produced or used. Monitoring data indicate that the general population may be exposed to 3-methylpentane via inhalation of ambient air, and dermal contact with this compound and other consumer products if applicable products containing 3-methylpentane. (SRC)

Air concn were obtained for 55 components of gasoline measured by 8 petroleum companies for service stations attendants (n=49), transport drivers (n=49), and outside operators (n=56) during the summer of 1984(2). The results for 3-methylpentane were (job category, mean concn (standard deviation), percent positive): outside operator, 0.447 (0.672) mg/cu m, 84%; transport drivers, 1.104 (2.109) mg/cu m, 100%; service attendant, 1.244 (1.007) mg/cu m, 100%). 3-Methylpentane constituted 2.3, 2.4 and 1.8% of the total hydrocarbon concn for these three work groups. Exposure of service station attendants was significantly reduced when vapor recovery systems were present(2). In longterm personal samples for 3-methylpentane obtained at a high volume service station in eastern Pennsylvania (n=18) 3 samples were 0.1-0.3 ppm and 15 were <0.1 ppm(1). 3-Methylpentane is often found in glue used in shoe manufacturing; of the 43 glues analyzed, 48% contained 3-methylpentane(3). The percent of 3-methylpentane in the glues ranged from 1-35% with a mean and median of 12% and 14%, respectively(3). 3-Methylpentane was not used in the 22 solvents analyzed that were used as glue diluents(3). Traffic emissions have been identified as a major source of 3-methylpentane detected in indoor air of office buildings in Greece(4). 3-Methylpentane was identified in 5 of 8 samples in New Jersey analyzed as part of the USEPA Total Exposure Assessment Methodology (TEAM) study(5).

AIR INTAKE: (assume median concn 1.6 ppb(1)): 0.11 mg; FOOD INTAKE: insufficient data; WATER INTAKE: insufficient data. (SRC)

3-Methylpentane was identified in 6 of the 12 samples of breath analyzed in Bayonne and Elizabeth, NJ as part of the USEPA Total Exposure Assessment Methodology (TEAM) study(1). It was also present in expired air from a control, prediabetic and diabetic population tested(2).

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational exposure or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal, aquatic, and plant life; and conformance with environmental and public health regulations.

/GUIDE 128: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE)/ Fire or Explosion: HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapor explosion hazard indoors, outdoors or in sewers. Those substances designated with a "P" may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids are lighter than water. Substances may be transported hot. /Hexanes/

/GUIDE 128: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE)/ Health: Inhalation or contact with material may irritate or burn skin and eyes. Fire may produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution. /Hexanes/

/GUIDE 128: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE)/ Public Safety: CALL Emergency Response Telephone Number ... . As an immediate precautionary measure, isolate spill or leak area for at least 50 meters (150 feet) in all directions. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate closed spaces before entering. /Hexanes/

/GUIDE 128: FLAMMABLE LIQUIDS (NON-POLAR/WATER-IMMISCIBLE)/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Structural firefighters' protective clothing will only provide limited protection. /Hexanes/

For more DOT Emergency Guidelines (Complete) data for 3-METHYLPENTANE (8 total), please visit the HSDB record page.

UN Hazard Class: 3; UN Pack Group: II