2-hexanone

H226: Flammable liquid and vapor [Warning Flammable liquids]

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

H361f ***: Suspected of damaging fertility [Warning Reproductive toxicity]

H372 **: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]

P203, P210, P233, P240, P241, P242, P243, P260, P261, P264, P270, P271, P280, P303+P361+P353, P304+P340, P318, P319, P370+P378, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

H226 (100%): Flammable liquid and vapor [Warning Flammable liquids]

H336 (100%): May cause drowsiness or dizziness [Warning Specific target organ toxicity, single exposure; Narcotic effects]

H361 (99.4%): Suspected of damaging fertility or the unborn child [Warning Reproductive toxicity]

H372 (99.7%): Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]

Aggregated GHS information provided per 317 reports by companies from 14 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.

H319: Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H335: May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

H361: Suspected of damaging fertility or the unborn child [Warning Reproductive toxicity]

H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure]

H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]

P203, P210, P233, P240, P241, P242, P243, P260, P261, P264, P264+P265, P270, P271, P280, P303+P361+P353, P304+P340, P305+P351+P338, P308+P316, P318, P319, P321, P337+P317, P370+P378, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

H303: May be harmful if swallowed [Warning Acute toxicity, oral]

H305: May be harmful if swallowed and enters airways [Warning Aspiration hazard]

H313: May be harmful in contact with skin [Warning Acute toxicity, dermal]

H373: May causes damage to organs through prolonged or repeated exposure [Warning Specific target organ toxicity, repeated exposure]

P210, P233, P240, P241, P242, P243, P260, P261, P264, P264+P265, P270, P271, P280, P301+P316, P301+P317, P302+P317, P303+P361+P353, P304+P340, P305+P351+P338, P319, P331, P337+P317, P370+P378, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

H361f: Suspected of damaging fertility [Warning Reproductive toxicity]

Fresh air, rest. Refer for medical attention.

Remove contaminated clothes. Rinse and then wash skin with water and soap. Refer for medical attention .

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

Rinse mouth. Do NOT induce vomiting. Refer for medical attention .

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment.

INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing.

INGESTION: DO NOT INDUCE VOMITING. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. Be prepared to transport the victim to a hospital if advised by a physician. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. IMMEDIATELY transport the victim to a hospital. (NTP, 1992)

(General first aid procedures)

Eye: Irrigate immediately - If this chemical contacts the eyes, immediately wash (irrigate) the eyes with large amounts of water, occasionally lifting the lower and upper lids. Get medical attention immediately.

Skin: Soap wash immediately - If this chemical contacts the skin, immediately wash the contaminated skin with soap and water. If this chemical penetrates the clothing, immediately remove the clothing, wash the skin with soap and water, and get medical attention promptly.

Breathing: Respiratory support

Swallow: Medical attention immediately - If this chemical has been swallowed, get medical attention immediately.

Excerpt from ERG Guide 127 [Flammable Liquids (Water-Miscible)]:

CAUTION: The majority of these products have a very low flash point. Use of water spray when fighting fire may be inefficient. CAUTION: For fire involving UN1170, UN1987 or UN3475, alcohol-resistant foam should be used. CAUTION: Ethanol (UN1170) can burn with an invisible flame. Use an alternate method of detection (thermal camera, broom handle, etc.).

SMALL FIRE: Dry chemical, CO2, water spray or alcohol-resistant foam.

LARGE FIRE: Water spray, fog or alcohol-resistant foam. Avoid aiming straight or solid streams directly onto the product. If it can be done safely, move undamaged containers away from the area around the fire.

FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2024)

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

If material is on fire or involved in fire: Do not extinguish fire unless flow can be stopped. Use water in flooding quantities as fog. Solid streams of water may spread fire. Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible. Use "alcohol" foam, dry chemical or carbon dioxide.

Water may be ineffective. Alcohol foam.

Excerpt from ERG Guide 127 [Flammable Liquids (Water-Miscible)]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 50 meters (150 feet) in all directions.

LARGE SPILL: Consider initial downwind evacuation for at least 300 meters (1000 feet).

FIRE: If tank, rail tank car or highway tank is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2024)

Personal protection: self-contained breathing apparatus. Collect leaking and spilled liquid in sealable containers as far as possible. Absorb remaining liquid in sand or inert absorbent. Then store and dispose of according to local regulations.

Environmental considerations -- land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ Dike surface flow using soil, sand bangs, foamed polyurethane, or foamed concrete. Absorb bulk liquid with fly ash, cement powder, or commercial sorbents.

Environmental considerations -- water spill: Use natural barriers or oil spill control booms to limit spill travel. Remove trapped material with suction hoses.

Environmental considerations -- air spill: Apply water spray or mist to knock down vapors.

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.

2-Hexanone was shown to undergo rapid (less than eight weeks) anaerobic biodegradation utilizing an anaerobic digester sludge inoculum.

The following wastewater treatment technologies have been investigated for 2-hexanone: Activated carbon.

Spray into the furnace. Incineration will become easier by mixing with a more flammable solvent. Recommendable method: Incineration.

If material not on fire and not involved in fire: Keep sparks, flames, and other sources of ignition away. Keep material out of water sources and sewers. Build dikes to contain flow as necessary. Attempt to stop leak if without undue personnel hazard. Use water spray to disperse vapors and dilute standing pools of liquid.

Personnel protection: Avoid breathing vapors. Keep upwind. ... Do not handle broken packages unless wearing appropriate personal protective equipment. Wash away any material which may have contacted the body with copious amounts of water or soap and water. Avoid bodily contact with the material.

SRP: The scientific literature for the use of contact lenses in industry is conflicting. The benefit or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

The worker should immediately wash the skin when it becomes contaminated.

For more Preventive Measures (Complete) data for 2-HEXANONE (6 total), please visit the HSDB record page.

Excerpt from ERG Guide 127 [Flammable Liquids (Water-Miscible)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. All equipment used when handling the product must be grounded. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. A vapor-suppressing foam may be used to reduce vapors. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. Use clean, non-sparking tools to collect absorbed material.

LARGE SPILL: Dike far ahead of liquid spill for later disposal. Water spray may reduce vapor, but may not prevent ignition in closed spaces. (ERG, 2024)

Fireproof. Separated from strong oxidants.

MATERIALS WHICH ARE TOXIC AS STORED OR WHICH CAN DECOMPOSE INTO TOXIC COMPONENTS ... SHOULD BE STORED IN A COOL WELL VENTILATED PLACE, OUT OF THE DIRECT RAYS OF THE SUN, AWAY FROM AREAS OF HIGH FIRE HAZARD, AND SHOULD BE PERIODICALLY INSPECTED. INCOMPATIBLE MATERIALS SHOULD BE ISOLATED ...

Biological Exposure Indices (BEI) [ACGIH] - 2,5-Hexanedione (free) in urine = 0.4 mg/L end of shift at end of workweek;

5.0 [ppm]

10 [ppm]

830 [ppm]

5000 [ppm]

1 ppm (4 mg/m³)

TWA 1 ppm (4 mg/m3)

100.0 [ppm]

100 ppm (410 mg/m³)

TWA 100 ppm (410 mg/m3) See Appendix G

1600 ppm (NIOSH, 2024)

1600.0 [ppm]

Excerpts from Documentation for IDLHs: Volunteers exposed to 1,000 ppm reported a strong odor and transient, moderate eye and nasal irritation [DiVencenzo et al. 1978].

1600 ppm

See: 591786

10.0 [ppm]

8 hr Time Weighted Avg (TWA): 5 ppm; 15 min Short Term Exposure Limit (STEL): 10 ppm, skin.

Biological Exposure Index (BEI): Determinant: 2,5-Hexanedione (without hydrolysis) in urine; Sampling Time: end of shift at end of workweek; BEI: 0.4 mg/L.

5 ppm as TWA; 10 ppm as STEL; (skin).

5 ppm [1995]

10 ppm [1995]

A harmful contamination of the air can be reached rather quickly on evaporation of this substance at 20 °C , on spraying or dispersing much faster.

The substance is irritating to the eyes and respiratory tract. The substance may cause effects on the nervous system. Exposure far above the OEL could cause unconsciousness.

Repeated or prolonged contact with skin may cause dermatitis. The substance may have effects on the nervous system.

Excerpt from NIOSH Pocket Guide for 2-Hexanone:

Skin: PREVENT SKIN CONTACT - Wear appropriate personal protective clothing to prevent skin contact.

Eyes: PREVENT EYE CONTACT - Wear appropriate eye protection to prevent eye contact.

Wash skin: WHEN CONTAMINATED - The worker should immediately wash the skin when it becomes contaminated.

Remove: WHEN WET (FLAMMABLE) - Work clothing that becomes wet should be immediately removed due to its flammability hazard (i.e., for liquids with a flash point <100 °F).

Change: No recommendation is made specifying the need for the worker to change clothing after the workshift. (NIOSH, 2024)

Wear appropriate personal protective clothing to prevent skin contact.

Wear appropriate eye protection to prevent eye contact.

Respirator Recommendations: Up to 10 ppm: (Assigned Protection Factor = 10) Any supplied-air respirator.

Respirator Recommendations: Up to 25 ppm: (Assigned Protection Factor = 25) Any supplied-air respirator operated in a continuous-flow mode.

For more Personal Protective Equipment (PPE) (Complete) data for 2-HEXANONE (8 total), please visit the HSDB record page.

Up to 10 ppm:

(APF = 10) Any supplied-air respirator

Up to 25 ppm:

(APF = 25) Any supplied-air respirator operated in a continuous-flow mode

Up to 50 ppm:

Methyl butyl ketone appears as a clear colorless liquid. Flash point 95 °F. Less dense than water. Vapors heavier than air.

Colorless liquid with an acetone-like odor; [NIOSH]

COLOURLESS LIQUID WITH CHARACTERISTIC ODOUR.

Colorless liquid with an acetone-like odor.

Colorless liquid

Characteristic acetone like odor, but more pungent

261 °F at 760 mmHg (NTP, 1992)

127.2 °C

127.60 °C. @ 760.00 mm Hg

126-128 °C

127.2 °C @760 [mm Hg]

-71 °F (NTP, 1992)

-55.5 °C

-56.9 °C

73 °F (NTP, 1992)

25 °C (closed cup)

95 °F (open cup)

77 °F (25 °C) (Closed cup)

23 °C c.c.

10 to 50 mg/mL at 72 °F (NTP, 1992)

1.4 wt% in water at 20 °C

Sol in acetone; miscible in ethanol and ether

In water, 1.72X10+4 mg/L at 20 °C

17.5 mg/mL at 20 °C

Solubility in water, g/100ml at 20 °C: 1.4

0.812 at 68 °F (USCG, 1999) - Less dense than water; will float

0.830 at 20 °C/20 °C

Relative density (water = 1): 0.8

0.83 @ 20°C

3.45 (NTP, 1992) - Heavier than air; will sink (Relative to Air)

3.5 (Air = 1)

Relative vapor density (air = 1): 3.5

2 mmHg at 68 °F ; 3.8 mmHg at 77 °F (NTP, 1992)

11.6 [mmHg]

11.6 mm Hg at 25 °C

Vapor pressure, kPa at 20 °C: 0.36

11.6 [mm Hg] @25 °C

log Kow = 1.38

795 °F (USCG, 1999)

795 °F (423 °C)

Highly flammable. Slightly soluble in water.

Highly Flammable

METHYL BUTYL KETONE is incompatible with oxidizing agents. It may also react with strong bases and reducing agents. (NTP, 1992)

Strong oxidizers.

Reacts violently with oxidants and may form unstable peroxides; attacks plastics

Strong oxidizers

CDC-ATSDR Toxicological Profile

2-Hexanone's toxicity is believed to be caused by covalent binding of its metabolites, especially 2,5-hexanedione, with axonal components of nerve tissue and inhibition of enzymes associated with the production of energy in this tissue. 2-Hexanone and 2,5-hexanedione may also inhibit sulfhydryl-dependent enzymes such as fructose-6-phosphate kinase and glyceraldehyde-3-phosphate dehydrogenase, as well as certain creatine kinases and adenylate kinases, impairing energy metabolism and subsequently resulting in axon deterioration. In addition, 2,5-hexanedione can covalently cross-links neurofilaments, causing large axonal swellings. (L176, A124, A125)

2-Hexanone

5 x 10 ^-3 mg/kg-day

3 x 10 ^-2 mg/m^3

Volatile Organic Compound (VOC)

Smith, C.D. and Nowell, L.H., 2024. Health-Based Screening Levels for evaluating water-quality data (3rd ed.). DOI:10.5066/F71C1TWP

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

Breathing 2-hexanone affects the nervous and reproductive systems. This may include pathologies such as peripheral neuropathy and developmental defects. (L176)

The substance can be absorbed into the body by inhalation and through the skin.

inhalation, skin absorption, ingestion, skin and/or eye contact

Oral (L176); inhalation (L176) ;dermal (L176)

Cough. Drowsiness. Headache. Nausea. Sore throat.

MAY BE ABSORBED! Dry skin.

Redness. Pain. Blurred vision.

Abdominal pain. Diarrhoea. Sore throat. Further see Inhalation.

irritation eyes, nose; peripheral neuropathy: lassitude (weakness, exhaustion), paresthesia; dermatitis; headache, drowsiness

Chronic 2-hexanone exposure causes weakness, numbness, tingling in the skin of the hands and feet, irritation to the lungs, and narcosis. (L176)

Body Weight, Neurological (Nervous System), Reproductive (Producing Children)

Eyes, skin, respiratory system, central nervous system, peripheral nervous system

Neurotoxin - Predominantly motor

Reproductive Toxin - A chemical that is toxic to the reproductive system, including defects in the progeny and injury to male or female reproductive function. Reproductive toxicity includes developmental effects. See Guidelines for Reproductive Toxicity Risk Assessment.

IRIS Current

LC50 (rat) = 8,000 ppm/4H

LD50: 2590 mg/kg (Oral, Rat) (T13)

LD50: 4800 mg/kg (Dermal, Rabbit) (T13)

LD50 Rat oral 2.59 g/kg

LD50 Rabbit dermal 4800 mg/kg

LD50 Mouse oral 2430 mg/kg

LD50 Rat oral 2590 mg/kg

Enhancement of MnBK neurotoxicity by MEK (methyl ethyl ketone) was reported ... Exposure of 225 ppm MnBK, 1125 ppm MEK, and 225 ppm MnBK plus 1125 ppm MEK in rats /indicated/ that the addition of high levels of MEK to a neurotoxic dose of MnBK shortened the onset of paralysis from 66 to 25 days ...

Inhalation of MEK (methyl ethyl ketone)/MnBK shortened hexobarbital sleeping time and increased in vitro production of n-aminophenol, formaldehyde, n-aminobenzoate, and sulfanilamide by rat hepatocyte microsomes ... Phenobarbital, also a microsomal inducer, protects against MnBK neurotoxicity ... Trans-1,2-dichloroethylene, an inhibitor of P450 2El, increased the exhaled MnBK concentration in rats not exposed to MnBK, presumably by decreasing the metabolism of endogeneous MnBK.

While MnBK itself does produce liver or kidney toxicity, exposure to MnBK is reported to enhance the activity of materials that are hepatotoxic or nephrotoxic. Prior exposure to an oral dose of MnBK followed by chloroform has been reported to enhance the toxicity, resulting in increased liver enzyme and urea nitrogen levels in the plasma, altered bile flow, and degenerative changes in hepatic and renal tissue. These effects are postulated to be due to alteration in P450 levels by MnBK. MnBK exposure may also alter the activity of other enzyme systems ... the inhibition of alcohol dehydrogenase by MnbK results in slower elimination of ethanol from the blood and prolongation of ethanol-induced loss of the righting reflex.

An accurate history is essential to determine whether a person has been exposed to /2-hexanone/. ...Patient may report weakness, muscle cramps, numbness, and paresthesias such as the feeling of tingling, burning, and freezing. Impotence may occur. The physical examination should examine all muscle groups for weakness. Peripheral muscles are affected first, with more proximal weakness after more prolonged exposure. Muscle stretch reflexes are absent distally in areas of weakness. Atrophy of the hand muscles has been reported. Hyperhidrosis may occur. All sensory modalities may be affected, including touch and proprioception. Patients should be assessed for cerebellar signs and tremor. Visual acuity and peripheral vision changes have not been reported, whereas blurred vision has. Tinnitus may occur. Signs of parkinsonism should be sought. ...The patient must be removed from all future exposure. Physical therapy should be initiated to maintain full range of motion until reinnervation occurs. Recovery is slow, as the regeneration of axon fibers must take place. Complete recovery of strength may not occur.

Basic treatment: Establish a patent airway. 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 ... . For contamination, flush eyes immediately with water. Irrigate each eye continuously with normal saline 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 ... . /Ketones and related compounds/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious or in respiratory arrest. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Monitor cardiac rhythm and treat arrhythmias if necessary ... . Start an IV with D5W /SRP: "To keep open", minimal flow rate/. Use lactated Ringer's if signs of hypovolemia are present. Watch for signs of fluid overload. Consider drug therapy for pulmonary edema ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Ketones and related compounds/

The measurement of 2,5-hexanedione in the urine after 8 hours of environmental exposure correlates well with the active air sampling of the workplace.

/HUMAN EXPOSURE STUDIES/ Human volunteers exposed to MnBK in air at 1000 ppm reported a strong odor and experienced transient, moderate eye and nasal irritation. Human pulmonary retention of inhaled MnBK is 60% to 90%, much greater than that for n-hexane, contributing to its increased neurotoxic potency.

/HUMAN EXPOSURE STUDIES/ In a series of 86 cases of peripheral polyneuropathy from 2-hexanone in human beings no impairment of visual fields or loss of visual acuity was reported which could be attributed to abnormality of optic nerves or retina.

/SIGNS AND SYMPTOMS/ 2-Hexanone vapor produces ocular and upper airway irritation. Brief exposures to high vapor concentrations of around 5000 ppm can produce drowsiness and central nervous system depression.

/SIGNS AND SYMPTOMS/ Afer chronic exposure to large amounts of /2-hexanone/, a syndrome of sensorimotor polyneuropathy may occur. Although motor findings predominate, diminished vibratory sensation has been observed. Studies of cardiac electrophysiology suggest that parasympathetic nerves may be affected.

LC50 Pimephales promelas (Fathead minnow, 31 days old) 428 mg/L/96 hr at 25 °C (99+% purity), flow-through bioassay.

2.00e+02

1.30e+03

3.10e+01

1.30e+02

3.80e+01

5.00e+01

8.80e-03

5.00e-03

3.00e-02

Volatile

3.28e+03

6.00e+02

4.00e+03

9.40e+01

3.90e+02

1.10e+02

2-Hexanone's production and use as a solvent for a wide variety of materials including lacquers, resins, oils, nitrocellulose, acrylates, vinyl, and alkyd coatings may result in its release to the environment through various waste streams. If released to air, a vapor pressure of 11.6 mm Hg at 25 °C indicates 2-hexanone will exist solely as a vapor in the atmosphere. Vapor-phase 2-hexanone 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 2 days. If released to soil, 2-hexanone is expected to have high mobility based upon an estimated Koc of 134. Volatilization from moist soil surfaces is expected to be an important fate process based upon an estimated Henry's Law constant of 9.3X10-5 atm-cu m/mole. 2-Hexanone may volatilize from dry soil surfaces based upon its vapor pressure. Theoretical 5-day BOD results of 59% and 61.4% degradation indicate that biodegradation may be an important environmental fate process. If released into water, 2-hexanone 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 7 and 164 hours, respectively. An estimated BCF of 2 suggests bioconcentration in aquatic organisms is low. Occupational exposure may be through inhalation and dermal contact with this compound at workplaces where 2-hexanone is produced or used. The general population may be exposed to 2-hexanone via inhalation of ambient air and the ingestion of food and drinking water containing 2-hexanone. (SRC)

2-Hexanone is known to occur in nature in only very low concentrations(1).

2-Hexanone's production and use as a solvent for a wide variety of materials including lacquers, resins, oils, nitrocellulose, acrylates, vinyl, and alkyd coatings(1,2) may result in its result in its release through various waste streams(SRC). 2-Hexanone has been identified as a disinfection by product of ozone treatment in drinking water(3).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 134(SRC), determined from a log Kow of 1.38(2) and a regression-derived equation(3), indicates that 2-hexanone is expected to have high mobility in soil(SRC). Volatilization of 2-hexanone from moist soil surfaces is expected to be an important fate process(SRC) given an estimated Henry's Law constant of 9.3X10-5 atm-cu m/mole(SRC), derived from its vapor pressure of 11.6 mm Hg(4) and water solubility of 17,200 mg/L(5). Volatilization from dry soil surfaces is expected(SRC) based upon the vapor pressure of this compound(4). Theoretical 5-day BOD results of 59%(6) and 61.4%(7) degradation indicate that biodegradation may be an important fate process in soil(SRC).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 134(SRC), determined from a log Kow of 1.38(2) and a regression-derived equation(3), indicates that 2-hexanone is not 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 9.3X10-5 atm-cu m/mole(SRC), derived from its vapor pressure, 11.6 mm Hg(4), and water solubility, 17,200 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 7 and 164 hours, respectively(SRC). According to a classification scheme(6), an estimated BCF 2(SRC), from its log Kow(2) and a regression-derived equation(7), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Theoretical 5-day BOD results of 59%(8) and 61.4%(9) degradation indicate that biodegradation may be an important fate process in water(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2-hexanone, which has a vapor pressure of 11.6 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 2-hexanone 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 about 2 days(3).

AEROBIC: Biodegradation is expected to be an important fate process for this compound(1). Using an acclimated mixed microbial culture seed, a 59% theoretical biological oxygen demand for 2-hexanone was obtained after five days(2). In a five day test using an activated microbial culture, 2-hexanone consumed 61.4% of its theoretical oxygen demand(4).

ANAEROBIC: 2-Hexanone was shown to undergo rapid (less than eight weeks) anaerobic biodegradation utilizing an anaerobic digester sludge inoculum(1).

The rate constant for the vapor-phase reaction of 2-hexanone with photochemically-produced hydroxyl radicals is 9.01X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 2.4 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). 2-Hexanone is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(2). 2-Hexanone does not contain chromospheres that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight(2).

An estimated BCF of 2 was calculated for 2-hexanone(SRC), using a log Kow of 1.38(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

The Koc of 2-hexanone is estimated as 134(SRC), using a log Kow of 1.38(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that 2-hexanone is expected to have high mobility in soil.

The Henry's Law constant for 2-hexanone is estimated as 9.3X10-5 atm-cu m/mole(SRC) derived from its vapor pressure, 11.6 mm Hg(1), and water solubility, 17,200 mg/L(2). This Henry's Law constant indicates that 2-hexanone is expected to volatilize 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 7 hours(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 7 days(SRC). 2-Hexanone's estimated Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). The potential for volatilization of 2-hexanone from dry soil surfaces may exist(SRC) based upon a vapor pressure of 11.6 mm Hg(1).

GROUNDWATER: 2-Hexanone was found in the Biscayne Aquifer groundwater in the vicinity of an inactive drum recycling facility in Dade County, FL, at a concn of 87 ug/L(1). Detected in two well water samples at an unauthorized hazardous waste disposal site in Lang township, NJ, maximum concn 14,000 ug/L, average concn 7,135 ug/L(2). 2-Hexanone was detected in three of eleven on site wells at an abandoned landfill in Tybouts Corner, DE, concn range 6.1-91.0 ug/L(3). 2-Hexanone was detected in the Biscayne Aquifer groundwater at concns of 150 and 110 ug/L(4). 2-Hexanone was detected, not quantified in the groundwater near waste disposal facilities in Michigan(5) and Quebec(6). 2-Hexanone was not detected in 78 shallow groundwater wells in southern New Jersey(7). For samples collected from 1981 to 1986, 2-hexanone was detected in 0.3%, 11.1%, 3.6% and 1.4% of the hazardous waste site groundwater samples in EPA regions 1, 2, 9 and 10, respectively(8). 2-Hexanone was not analyzed in EPA region 7, and was not detected in regions 3, 4, 5, 6 and 8(8).

DRINKING WATER: 2-Hexanone was not detected in drinking water samples from the Sea of Galilee, Israel water treatment plants in May of 1999, September of 1999 and July of 2000(1).

SURFACE WATER: 2-Hexanone was detected in Lake Erie at a concn of 1 ug/L(1) and an on-site lagoon at an unauthorized hazardous waste disposal site in Lang township, NJ, at a maximum concn of 30 ug/L, and average concn of 20 ug/L(2).

2-Hexanone was found in process water from in-situ coal gasification in Gillette, WY (7 ppm), in the aqueous condensate from low-Btu gasification of rosebud coal in Morgantown, WV (202 ppm), and in retort water from in-situ oil shale processing at Rock Springs, WY (53 ppm)(1). Detected in the leachate of various municipal landfills at an average concn of 0.148 mg/L(2). Identified in leachate discharge into a ditch near an abandoned landfill in Tybouts Corner, DE, 380 ug/L(3). Detected, not quantified in one out of sixty-three effluent and twenty-two intake waters from a wide range of chemical manufacturing areas across the US(4). Detected in the effluent of 8 solid waste disposal facilities in the US with a maximum observed concn of 6,600 ug/L(5) and in the leachate of a waste disposal facility in Japan at a concn of 49.9 ug/L(6). 2-Hexanone was detected in the effluent of an incineration plant in Germany at a concn of 1.6 ug/cu m(7) and in the leachate of a sand and gravel pit near Utica, NY at a concn of 13 ug/L(8).

SOIL: 2-Hexanone was found in soil samples at an unauthorized hazardous waste disposal site in Lang township, NJ, at a maximum concn of 440 ug/kg (surface soil) and 46 ug/kg (subsurface soil)(1).

SEDIMENT: 2-Hexanone was detected in one out of three sediment samples in Red Lion creek near an abandoned landfill in Tybouts County, DE, in concns less than 850 ug/L(1).

URBAN/SUBURBAN: 2-Hexanone was detected, not quantified in suburban samples (Tubingen) West Germany(1). 2-Hexanone was identified in 1 of 13 outdoor samples in Helsinki, Finland(2).

INDOOR AIR: 2-Hexanone was identified, not quantified in 46% of homes and buildings monitored in Finland(1). 2-Hexanone was found in 4 of 15 indoor samples in Helsinki, Finland(2).

RURAL/REMOTE: 2-Hexanone was detected, not quantified in air samples from the Southern Black Forest (Kalbelescheuer)(1,2). 2-Hexanone was detected, not quantified in air samples in Whitaker's Forest, California(3).

2-Hexanone has been identified, not quantified as a component of the aromatic fraction of blue cheese(1) and Beaufort (Gruyere) cheese(2). 2-Hexanone has been identified, not quantified as a component of raw chicken breast muscle(3). 2-Hexanone has been identified, not quantified as a volatile component of roasted filberts(4), nectarines(5), mutton(6), chicken(6), beef(6,7) and cognac(8). 2-Hexanone has been detected in white bread, toasted oats and uncured beef (0.38 mg/kg)(6). 2-Hexanone has been detected in canned cream (1 ppb), canned kernel (2 ppb), frozen kernel (<5 ppb) and fresh kernel (<1 ppb) corn products(9).

2-Hexanone was found in Charybdis feriatus crabs at 0.5 ug/kg, 1.0 ug/kg, and 3.6 ug/kg in the leg, body and carapace, respectively(1).

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.

2-Hexanone was shown to undergo rapid (less than eight weeks) anaerobic biodegradation utilizing an anaerobic digester sludge inoculum.

The following wastewater treatment technologies have been investigated for 2-hexanone: Activated carbon.

Spray into the furnace. Incineration will become easier by mixing with a more flammable solvent. Recommendable method: Incineration.

49 092 42; Methyl butyl ketone (Flammable liquid, not otherwise specified)

Flammable Liquid

Symbol: T; R: 10-48/23-62-67; S: (1/2)-36/37-45

UN Hazard Class: 3; UN Pack Group: III