O-Xylene

H226: Flammable liquid and vapor [Warning Flammable liquids]

H312: Harmful in contact with skin [Warning Acute toxicity, dermal]

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

H332: Harmful if inhaled [Warning Acute toxicity, inhalation]

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

H225 (26.7%): Highly Flammable liquid and vapor [Danger Flammable liquids]

H226 (73.3%): Flammable liquid and vapor [Warning Flammable liquids]

H304 (32%): May be fatal if swallowed and enters airways [Danger Aspiration hazard]

H312+H332 (32.6%): Harmful in contact with skin or if inhaled [Warning Acute toxicity, dermal; acute toxicity, inhalation]

H312 (> 99.9%): Harmful in contact with skin [Warning Acute toxicity, dermal]

H315 (100%): Causes skin irritation [Warning Skin corrosion/irritation]

H319 (59%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H332 (> 99.9%): Harmful if inhaled [Warning Acute toxicity, inhalation]

H335 (32.1%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

H412 (26.9%): Harmful 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, P317, P319, P321, P331, P332+P317, P337+P317, P362+P364, P370+P378, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

Aggregated GHS information provided per 1649 reports by companies from 34 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.

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

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

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

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

H400: Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

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

P210, P233, P240, P241, P242, P243, P260, P261, P264, P270, P271, P273, P280, P301+P316, P303+P361+P353, P304+P340, P308+P316, P317, P319, P321, P331, P370+P378, P391, 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]

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

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

P203, P210, P233, P240, P241, P242, P243, P261, P264, P264+P265, P271, P280, P301+P316, P301+P317, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P318, P319, P321, P331, P332+P317, P337+P317, P362+P364, P370+P378, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

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

H402: Harmful to aquatic life [Hazardous to the aquatic environment, acute hazard]

H412: Harmful to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

Fresh air, rest. Refer for medical attention.

First rinse with plenty of water for at least 15 minutes, then remove contaminated clothes and rinse again. 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. 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 promptly - If this chemical contacts the skin, promptly wash the contaminated skin with soap and water. If this chemical penetrates the clothing, promptly remove the clothing and wash the skin with soap and water. Get medical attention promptly.

Breathing: Respiratory support

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

Fire Extinguishing Agents Not to Be Used: Water may be ineffective.

Fire Extinguishing Agents: Foam, dry chemical, or carbon dioxide (USCG, 1999)

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

Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical, or carbon dioxide.

Advice for firefighters: Wear self-contained breathing apparatus for firefighting if necessary.

Use water spray to cool unopened containers.

Foam, dry chemical, or carbon dioxide. Water may be ineffective. Cool exposed containers with water.

Excerpt from ERG Guide 130 [Flammable Liquids (Water-Immiscible / Noxious)]:

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: filter respirator for organic gases and vapours adapted to the airborne concentration of the substance. Ventilation. Remove all ignition sources. Do NOT let this chemical enter the environment. 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.

ACCIDENTAL RELEASE MEASURES: Personal precautions, protective equipment and emergency procedures: Use personal protective equipment. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Remove all sources of ignition. Evacuate personnel to safe areas. Beware of vapors accumulating to form explosive concentrations. Vapors can accumulate in low areas. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided. Methods and materials for containment and cleaning up: Contain spillage, and then collect with an electrically protected vacuum cleaner or by wet-brushing and place in container for disposal according to local regulations.

Stop discharge if possible. Keep people away. Call fire department. Avoid contact with liquid and vapor. Isolate and remove discharged material. Notify local health and pollution control agencies.

Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number U239 and F003, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Product: Contact a licensed professional waste disposal service to dispose of this material. Burn in a chemical incinerator equipped with an afterburner and scrubber but exert extra care in igniting as this material is highly flammable. Offer surplus and non-recyclable solutions to a licensed disposal company; Contaminated packaging: Dispose of as unused product.

SRP: Contaminated protective clothing should be segregated in a manner such that there is no direct personal contact by personnel who handle, dispose, or clean the clothing. The completeness of the cleaning procedures should be considered before the decontaminated protective clothing is returned for reuse by the workers. Contaminated clothing should not be taken home at the end of shift, but should remain at employee's place of work for cleaning.

ACCIDENTAL RELEASE MEASURES: Personal precautions, protective equipment and emergency procedures: Use personal protective equipment. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Remove all sources of ignition. Evacuate personnel to safe areas. Beware of vapors accumulating to form explosive concentrations. Vapors can accumulate in low areas. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided.

Precautions for safe handling: Avoid contact with skin and eyes. Avoid inhalation of vapor or mist. Keep away from sources of ignition - No smoking. Take measures to prevent the build up of electrostatic charge.

Appropriate engineering controls: Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and at the end of workday.

For more Preventive Measures (Complete) data for 2-XYLENE (7 total), please visit the HSDB record page.

SMALL SPILLS AND LEAKAGE: If you should spill this chemical, use absorbent paper to pick up all liquid spill material. Your contaminated clothing and absorbent paper should be sealed in a vapor-tight plastic bag for eventual disposal. Solvent wash all contaminated surfaces with acetone followed by washing with a strong soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.

STORAGE PRECAUTIONS: You should store this material in a refrigerator. (NTP, 1992)

Fireproof. Store only in original container. Separated from strong oxidants and strong acids. Store in an area without drain or sewer access.

Keep container tightly closed in a dry and well-ventilated place. Containers which are opened must be carefully resealed and kept upright to prevent leakage. Storage class (TRGS 510): Flammable liquids.

TWA 100 ppm (435 mg/m3) ST 150 ppm (655 mg/m3)

TWA 100 ppm (435 mg/m3) See Appendix G

900 ppm (NIOSH, 2024)

See: 95476

8 hr Time Weighted Avg (TWA): 100 ppm; 15 min Short Term Exposure Limit (STEL): 150 ppm. /Xylene (o-, m-, & p-isomers)/

Biological Exposure Index (BEI): Determinant: methylhippuric acids in urine; Sampling Time: end of shift; BEI: 1.5 g/g creatinine. /Xylenes, technical or commercial grade/

A4; Not classifiable as a human carcinogen. /Xylene (o-,m-, & p- isomers)/

100 ppm as TWA; 150 ppm as STEL; A4 (not classifiable as a human carcinogen); BEI issued.

221 mg/m

Acute Inhalation: 2 ppm (L165)

Intermediate Inhalation: 0.6 ppm (L165)

Chronic Inhalation: 0.05 ppm (L165)

Acute Oral: 1 mg/kg/day (L165)

Intermediate Oral: 0.4 mg/kg/day (L165)

Chronic Oral: 0.2 mg/kg/day (L165)

DOE Protective Action Criteria (PAC): Temporary Emergency Exposure Limits (TEELs) for 2-Xylene: TEEL-0: 100 ppm; PAC-1: 150 ppm; PAC-2: 200 ppm; PAC-3: 900 ppm (TEEL-0: The threshold concentration below which most people will experience no adverse health effects; PAC-1: The maximum concentration in air below which it is believed nearly all individuals could be exposed for up to one hour without experiencing other than mild transient adverse health effects or perceiving a clearly defined objectionable odor; PAC-2: The maximum concentration in air below which it is believed nearly all individuals could be exposed for up to one hour without experiencing or developing irreversible or other serious health effects or symptoms that could impair their abilities to take protective action; PAC-3: The maximum concentration in air below which it is believed nearly all individuals could be exposed for up to one hour without experiencing or developing life-threatening health effects).

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

The substance is irritating to the eyes and skin. If this liquid is swallowed, aspiration into the lungs may result in chemical pneumonitis. The substance may cause effects on the central nervous system. This may result in impaired functions.

The substance defats the skin, which may cause dryness or cracking. The substance may have effects on the central nervous system. Animal tests show that this substance possibly causes toxicity to human reproduction or development.

Excerpt from NIOSH Pocket Guide for o-Xylene:

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)

Eye/face protection: Face shield and safety glasses. Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).

Skin protection: Handle with gloves.

Body Protection: Complete suit protecting against chemicals. Flame retardant antistatic protective clothing. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.

Respiratory protection: Where risk assessment shows air-purifying respirators are appropriate use a full-face respirator with multipurpose combination (US) or type ABEK (EN 14387) respirator cartridges as a backup to engineering controls. If the respirator is the sole means of protection, use a full-face supplied air respirator. Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).

For more Personal Protective Equipment (PPE) (Complete) data for 2-XYLENE (10 total), please visit the HSDB record page.

NIOSH/OSHA

Up to 900 ppm:

(APF = 10) Any chemical cartridge respirator with organic vapor cartridge(s)*

(APF = 25) Any powered, air-purifying respirator with organic vapor cartridge(s)*

(APF = 10) Any supplied-air respirator*

(APF = 50) Any self-contained breathing apparatus with a full facepiece

Emergency or planned entry into unknown concentrations or IDLH conditions:

(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode

(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus

(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister

Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

NO open flames, NO sparks and NO smoking. Above 30 °C use a closed system, ventilation and explosion-proof electrical equipment. Prevent build-up of electrostatic charges (e.g., by grounding). NO contact with incompatible materials: See Chemical Dangers

Use local exhaust or breathing protection.

Protective gloves.

O-xylene appears as a colorless watery liquid with a sweet odor. Less dense than water. Insoluble in water. Irritating vapor. (USCG, 1999)

COLOURLESS LIQUID WITH CHARACTERISTIC ODOUR.

Colorless liquid with an aromatic odor.

Colorless liquid

Aromatic odor

289 to 293 °F at 760 mmHg (NTP, 1992)

144.5 °C

-13 to -9 °F (NTP, 1992)

-25.16 °C

63 °F (NTP, 1992)

31.0 °C (87.8 °F) - closed cup

63 °F; 17 °C (Closed cup)

30 °C c.c.

Insoluble (NTP, 1992)

In water, 1.78X10+2 mg/L at 25 °C

In water, 180 mg/L at 25 °C (average of 16 literature values ranging from 167-221 mg/L at 25 °C)

Miscible with ethanol, ethyl ether, acetone, petroleum ether, benzene, carbon tetrachloride

Soluble with most organic solvents.

Solubility in water, g/l at 20 °C: 0.18 (very slightly soluble)

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

0.8801 at 20 °C/4 °C

Critical density: 2.71 mmol/cu cm; Critical volume: 369.0 cu cm/mol

Relative density (water = 1): 0.88 (20 °C)

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

3.7 (Air = 1)

Relative vapor density (air = 1): 3.7

10 mmHg at 89.8 °F (NTP, 1992)

6.65 mm Hg at 25 °C /extrapolated/

Vapor pressure, kPa at 20 °C: 0.7

log Kow = 3.12

Henry's Law constant = 5.18X10-3 atm-cu m/mol at 25 °C

Stable under recommended storage conditions.

869 °F (USCG, 1999)

867 °F (463 °C)

Hazardous decomposition products formed under fire conditions - Carbon oxides.

When heated to decomp it emits acrid smoke and irritating fumes.

0.760 mPa.s at 25 °C

0.81 mPa*s at 20 °C

No reaction with common materials

-17,558 Btu/lb = -9754.7 cal/g = -408.41 X 105 J/kg

Highly flammable. Insoluble in water.

Hydrocarbons, Aromatic

Highly Flammable

O-XYLENE may react with oxidizing materials. (NTP, 1992).

Incompatible materials: Oxidizing agents.

Strong oxidizers, strong acids.

Strong oxidizers, strong acids

IDENTIFICATION AND USE: 2-Xylene (o-xylene) is a colorless liquid. It is used in manufacture of phthalic anhydride, vitamin and pharmaceutical syntheses, dyes, insecticides, motor fuels. HUMAN EXPOSURE AND TOXICITY: Severe toxic effects result from exposure to o-xylene at 1,000 ppm or 4,410 mg/cu m for 60 minutes. Symptoms of illness result from exposure to 300 ppm or 1,323 mg/ cu m for 60 minutes. Levels of xylenes in blood reflect recent exposure. The m-and p-xylene isomers usually are measured together and reported as m/p-xylene; the o-xylene isomer is measured and reported separately. ANIMAL STUDIES: In a study on the noradrenaline and dopamine levels in various parts of the forebrain and hypothalamus, rats (six males/group) were exposed to 0 or 2000 ppm o-xylene 6 hr/day for 3 days. The animals were killed within 18 hr after final exposure. There was a significant increase in catecholamine levels and turnover in various parts of the hypothalamus and a decrease in the dopamine turnover in the forebrain of exposed animals. Administration of xylenes to rats caused decreases in liver glutathione (GSH) concentrations, reduction in glutathione concentration was most pronounced after treatment with o-xylene isomer (4.0 mmol/kg). Exposure of rats to 2000 ppm of o-xylene for 3 days increased hepatic cytochrome P450 concentration and reduced nicotinamide adenine dinucleotide cytochrome C reductase activity. In kidney microsomes an increased concentration of cytochrome P450 was obtained following exposure to o-xylene. Exposures at 1450 ppm of o-xylene reduced the respiratory rate of mice 50% in a manner consistent with sensory irritation. Comparison of the individual xylene isomers showed that the irritant effects of m- and o-xylene as quantified by measurements of respiratory rate in mice are more pronounced than those of p-xylene, with o-xylene having the most prolonged effect. Rats, guinea-pigs, monkeys, and dogs were exposed either to 780 ppm (3368 mg/cu m) o-xylene for 8 hours per day on five days per week for six weeks or to 78 ppm (337 mg/cu m) continuously for 90 days. No significant change in body weight or in hematological parameters and no significant toxicity were observed after histopathological examination of all major organs. Male rats inhaling air containing o-xylene, 4750 mg/cu m/8 hr/day, for 1 yr, had no pathological alterations in liver morphology, but increased levels of liver cytochrome P450, cytochrome B5, nicotinamide adenine dinucleotide phosphate cytochrome C reductase, aminopyrine N-demethylase, and aniline hydroxylase. o-Xylene also increased food and water consumption and relative liver wt. Mice were exposed to 0 or 115 ppm o-xylene for 4 hr, 3 times per day on day 6 to day 15 of gestation, and the dams were killed on day 18. There was evidence of delayed weight gain and skeletal ossification in the fetuses of exposed animals. When rabbits were exposed to 0 or 115 ppm o-xylene 24 hr/day from day 7 to day 20 of gestation, no maternal toxicity or incidence of delayed development was observed in the exposed group. None of the isomers nor unspecified xylene was mutagenic to Salmonella typhimurium TA1535, TA1537, TA98, TA100, UTH 8413 or UTH8414 in the presence or absence of a metabolic activation. None of the xylene isomers induced micronuclei in the bone marrow of male mice after two ip administrations of 105-650 mg/kg body weight at a 24-hr interval, but they did, however, enhance the induction of micronuclei by toluene. ECOTOXICITY STUDIES: The xylene isomers have a similar degree of toxicity as mixed xylenes to estuarine/marine invertebrates. For o-xylene, acute toxicity values range from the 96-hour embryo lethality EC50 value of 4.1 mg/L in sea urchin eggs, to the 48-hour LC50 value of 24.7 mg/L in brine shrimp. Results of these studies indicate that o-xylene is slightly to moderately toxic to estuarine/marine invertebrates on an acute basis.

o-Xylene is a cholinesterase or acetylcholinesterase (AChE) inhibitor. A cholinesterase inhibitor (or 'anticholinesterase') suppresses the action of acetylcholinesterase. Because of its essential function, chemicals that interfere with the action of acetylcholinesterase are potent neurotoxins, causing excessive salivation and eye-watering in low doses, followed by muscle spasms and ultimately death. Nerve gases and many substances used in insecticides have been shown to act by binding a serine in the active site of acetylcholine esterase, inhibiting the enzyme completely. Acetylcholine esterase breaks down the neurotransmitter acetylcholine, which is released at nerve and muscle junctions, in order to allow the muscle or organ to relax. The result of acetylcholine esterase inhibition is that acetylcholine builds up and continues to act so that any nerve impulses are continually transmitted and muscle contractions do not stop. Among the most common acetylcholinesterase inhibitors are phosphorus-based compounds, which are designed to bind to the active site of the enzyme. The structural requirements are a phosphorus atom bearing two lipophilic groups, a leaving group (such as a halide or thiocyanate), and a terminal oxygen.

o-Xylene

Volatile Organic Compound (VOC)

data are for xylenes, CASRN 1330207

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

Evaluation: There is inadequate evidence in humans for the carcinogenicity of xylenes. There is inadequate evidence in experimental animals for the carcinogenicity of xylenes. Overall classification: Xylenes are not classifiable as to their carcinogenicity to humans (Group 3)./Xylenes, o,m,p isomers/

CLASSIFICATION: D; not classifiable as to human carcinogenicity. BASIS FOR CLASSIFICATION: Orally administered technical xylene mixtures did not result in significant increases in incidences in tumor responses in rats or mice of both sexes. HUMAN CARCINOGENICITY DATA: None. ANIMAL CARCINOGENICITY DATA: Inadequate. /based on former classification system/

Under the Draft Revised Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1999), data are inadequate for an assessment of the carcinogenic potential of xylenes. Adequate human data on the carcinogenicity of xylenes are not available, and the available animal data are inconclusive as to the ability of xylenes to cause a carcinogenic response. Evaluations of the genotoxic effects of xylenes have consistently given negative results. /Xylenes/

A4; Not classifiable as a human carcinogen. /Xylene (o-, m-, & p-isomers)/

3, not classifiable as to its carcinogenicity to humans. (L135)

Acute exposure to cholinesterase inhibitors can cause a cholinergic crisis characterized by severe nausea/vomiting, salivation, sweating, bradycardia, hypotension, collapse, and convulsions. Increasing muscle weakness is a possibility and may result in death if respiratory muscles are involved. Accumulation of ACh at motor nerves causes overstimulation of nicotinic expression at the neuromuscular junction. When this occurs symptoms such as muscle weakness, fatigue, muscle cramps, fasciculation, and paralysis can be seen. When there is an accumulation of ACh at autonomic ganglia this causes overstimulation of nicotinic expression in the sympathetic system. Symptoms associated with this are hypertension, and hypoglycemia. Overstimulation of nicotinic acetylcholine receptors in the central nervous system, due to accumulation of ACh, results in anxiety, headache, convulsions, ataxia, depression of respiration and circulation, tremor, general weakness, and potentially coma. When there is expression of muscarinic overstimulation due to excess acetylcholine at muscarinic acetylcholine receptors symptoms of visual disturbances, tightness in chest, wheezing due to bronchoconstriction, increased bronchial secretions, increased salivation, lacrimation, sweating, peristalsis, and urination can occur. Certain reproductive effects in fertility, growth, and development for males and females have been linked specifically to organophosphate pesticide exposure. Most of the research on reproductive effects has been conducted on farmers working with pesticides and insecticdes in rural areas. In females menstrual cycle disturbances, longer pregnancies, spontaneous abortions, stillbirths, and some developmental effects in offspring have been linked to organophosphate pesticide exposure. Prenatal exposure has been linked to impaired fetal growth and development. Neurotoxic effects have also been linked to poisoning with OP pesticides causing four neurotoxic effects in humans: cholinergic syndrome, intermediate syndrome, organophosphate-induced delayed polyneuropathy (OPIDP), and chronic organophosphate-induced neuropsychiatric disorder (COPIND). These syndromes result after acute and chronic exposure to OP pesticides.

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

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

Oral(L165) ; inhalation (L165) ; dermal (L165)

Dizziness. Drowsiness. Headache. Nausea.

Dry skin. Redness.

Redness. Pain.

Burning sensation. Abdominal pain. Further see Inhalation.

irritation eyes, skin, nose, throat; dizziness, excitement, drowsiness, incoordination, staggering gait; corneal vacuolization; anorexia, nausea, vomiting, abdominal pain; dermatitis

Dizziness, drowsiness, headache, and nausea can follow ihnalation and ingestion exposure. Burning sensations and abdominal pain can also result from ingestion. Dry skin, redness, and pain can result from dermal and eye exposure depending on the route of exposure. Conjunctivitis, dermatitis, irritation to respiratory tract, dyspnea, anorexia, vomiting, fatigue, vertigo, incoordination, irritation, gangrene and anemia can also follow xylene poisoning. (A579)

Eyes, skin, respiratory system, central nervous system, gastrointestinal tract, blood, liver, kidneys

SURROGATE. See Xylenes

LD50: 4595 ppm (Inhalation, Mouse) (L165)

LD50 Rat oral 3608 mg/kg bw

LC50 Mouse inhalaton 4600 ppm for 6 hr exposure.

LC50 Rat inhalation 6350 ppm (27.4 mg/L)/4 hr /From table/

LC50 Rat inhalation 6700 ppm (29 mg/L)/4 hr /From table/

For more Non-Human Toxicity Values (Complete) data for 2-XYLENE (7 total), please visit the HSDB record page.

If the compound has been ingested, rapid gastric lavage should be performed using 5% sodium bicarbonate. For skin contact, the skin should be washed with soap and water. If the compound has entered the eyes, they should be washed with large quantities of isotonic saline or water. In serious cases, atropine and/or pralidoxime should be administered. Anti-cholinergic drugs work to counteract the effects of excess acetylcholine and reactivate AChE. Atropine can be used as an antidote in conjunction with pralidoxime or other pyridinium oximes (such as trimedoxime or obidoxime), though the use of '-oximes' has been found to be of no benefit, or possibly harmful, in at least two meta-analyses. Atropine is a muscarinic antagonist, and thus blocks the action of acetylcholine peripherally.

Male Wistar rats were exposed by inhalation for 4 hr to 1000 mg/cu m (230 ppm) of o-xylene or 1700 ppm of acetone alone, or in combination. In the combination exposure, blood xylene immediately after the exposure was increased by 40% whereas the blood acetone level was decreased by 15%. In a corresponding study, H-strain mice were exposed for 2 hr to 1392 mg/cu m (320 ppm) of o-xylene or 6655 mg/cu m (1530 ppm) of acetone alone or in combination. The combination exposure was accompanied by a 33% increase of the blood xylene concentration whereas the blood acetone level was decreased by 18%.

Immediate First Aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Aromatic hydrocarbons and related compounds/

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 ... . Monitor for shock 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 L of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool. Administer activated charcoal ... . /Aromatic 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 ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias if necessary ... . Start IV administration of D5W TKO /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 (Valium) or lorazepam (Ativan) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Aromatics hydrocarbons and related compounds/

Emergency and supportive measures: Inhalation exposure. Maintain an open airway and assist ventilation if necessary. Administer supplemental oxygen and monitor oxygenation. If the patient is coughing or dyspneic, consider aspiration pneumonia. Treat for hydrocarbon pneumonia. If the patient remains asymptomatic after a 6-hour observation, chemical pneumonia is unlikely, and further observation or chest radiography is not needed. Treat coma, arrhythmias and bronchospasm if they occur. Caution: Epinephrine and other sympathomimetic amines may provoke or aggravate cardiac arrhythmias. Tachyarrhythmias may be treated with propranolol ... or esmolol. /Toluene and xylene/

Decontamination: Patients exposed only to solvent vapor who have no skin or eye irritation do not need decontamination. However, victims whose clothing or skin is contaminated with liquid can secondarily contaminate response personnel by direct contact or through off-gassing vapor. Inhalation. Remove the victim from exposure and give supplemental oxygen if available. Skin and eyes. Remove contaminated clothing and wash exposed skin with soap and water. Flush exposed or irritated eyes with plain water or saline. Ingestion. Administer activated charcoal orally if conditions are appropriate. Consider gastric lavage for large ingestions (>1-2 oz) if it can be performed within 30 minutes of ingestion. /Toluene and xylene/

/HUMAN EXPOSURE STUDIES/ After oral administration of o-xylene (39 mg/kg body weight) maximum urinary levels of glycine and glucuronide conjugates of o-methylbenzoic acid were reported to be 33.1 and 1.0% of the administered dose, respectively. Similar values were obtained after an oral dose of 78 mg/kg body weight. About 4-5% of the dose absorbed in the lungs is exhaled unchanged after exposure to 870 mg/cu m (200 ppm) xylene. Elimination in exhaled breath is reported to follow a similar triphasic profile to that for urinary excretion of methylbenzoic acid conjugates. An initial half-time of about one hour was obtained in a study.

/HUMAN EXPOSURE STUDIES/ The quantitative relationship between exposure to xylene vapor and urinary excretion in methylhippuric acid isomers were studied in the second half of a working wk. The participants in the study were 121 male workers engaged in dip-coating of metal parts who were predominantly exposed to three xylene isomers. The intensity of exposure measured by diffusive sampling during an 8-hr shift was such that the geometric mean vapor concentration was 3.8 ppm for xylenes (0.8 ppm for o-xylene, 2.1 ppm for m-xylene, and 0.9 ppm for p-xylene), 0.8 ppm for toluene, and 0.9 ppm for ethylbenzene. Urine samples were collected at the end of the shift and analyzed for metabolites by HPLC. The statistical analysis showed that there is a linear relationship between the intensity of exposure to xylenes and the concn of methylhippuric acid in urine, that the regression line passes very close to the origin, and that the increment in observed (i.e., noncorrected) methylhippuric acid concn as a function of incr xylene concn was 17.8 mg/ppm. Further exam on the basis on individual xylene isomers showed that the slopes of the regression lines for o- and m-isomers were similar (i.e., 17.1 and 16.6 mg/L/ppm, respectively), whereas that for p-xylene was larger (21.3 mg/L/ppm).

/SIGNS AND SYMPTOMS/ Severe toxic effects result from exposure to o-xylene at 1,000 ppm or 4,410 mg/cu m for 60 minutes. Symptoms of illness result from exposure to 300 ppm or 1,323 mg/ cu m for 60 minutes. Exposure to 100 ppm or 441 mg/cu m for 60 minutes is considered unsatisfactory.

/EPIDEMIOLOGY STUDIES/ To study the relationship between acute air pollution exposure and cardiovascular events during labor/delivery. The Consortium on Safe Labor (2002-2008), an observational US cohort with 223,502 singleton deliveries provided electronic medical records. Air pollution exposure was estimated by modified Community Multiscale Air Quality models. Cardiovascular events (cardiac failure/arrest, stroke, myocardial infarcts and other events) were recorded in the hospital discharge records for 687 pregnancies (0.3%). Logistic regression with generalized estimating equations estimated the relationship between cardiovascular events and daily air pollutant levels for delivery day and the 7 days preceding delivery. Increased odds of cardiovascular events were observed for each IQR increase in exposure to nitric oxides at 5 and 6 days prior to delivery (OR=1.17, 99% CI 1.04 to 1.30 and OR=1.15, 1.03 to 1.28, respectively). High exposure to toxic air pollution species such as ethylbenzene (OR=1.50, 1.08 to 2.09), m-xylene (OR=1.54, 1.11 to 2.13), o-xylene (OR=1.51, 1.09 to 2.09), p-xylene (OR=1.43, 1.03 to 1.99) and toluene (OR=1.42, 1.02 to 1.97) at 5 days prior to delivery were also associated with cardiovascular events. Decreased odds of events were observed with exposure to ozone. Air pollution in the days prior to delivery, especially nitrogen oxides and some toxic air pollution species, was associated with increased risk of cardiovascular events during the labor/delivery admission.

LC50; Species: Cancer magister (crab) larvae stage I; Concentration: 6 ppm for 96 hr /Conditions of bioassay not specified/

LC50; Species: Crangon franciscorum (Shrimp); Concentration: 1.3 ppm for 96 hr /Conditions of bioassay not specified/

EC50; Species: Chlorella vulgaris (Green algae); Conditions: freshwater, static, 20 °C; Concentration: 55000 ug/L for 24 hr; Effect: growth, general /formulated product/

EC50; Species: Pseudokirchneriella subcapitata (Green algae); Conditions: freshwater, static; Concentration: 4700 ug/L for 72 hr; Effect: growth, general /formulated product/

For more Ecotoxicity Values (Complete) data for 2-XYLENE (19 total), please visit the HSDB record page.

/AQUATIC SPECIES/ ... Cod eggs (Gadus morhus L.) /were exposed/ to xylene isomers in covered glass dishes and monitored the effects both during fertilization and during early cleavage of fertilized eggs ... o-Xylene had no significant effect on the fertilization rate at concentrations of 16-35 mg/L. Fertilized eggs were exposed to xylene for 3 or 6 hr before first cleavage. No significant difference was observed between the individual xylene isomers or between the two exposure periods. Effects on the early cleavage pattern were significant for xylene concentrations between 2 and 7 mg/L. The effects seen included inhibition of formation of the cleavage furrow. Small cells or a total absence of cleavage occurred on exposure to all isomers at concentrations of 16-35 mg/L, while incomplete or uneven cleavage was found at exposures of 8-15 mg/L.

/AQUATIC SPECIES/ ... Juvenile coho salmon were able to significantly avoid o-xylene concentrations of >/= 0.2 mg/L water.

/AQUATIC SPECIES/ Sea urchin (Strongy locentrotus droebachiensis) eggs /were exposed/ to o-xylene from fertilization and monitored deaths, pathology, inhibition of cleavage and differentiation, and pigment effects. Eggs were maintained in test beakers covered with aluminium foil. A 96-hr EC50, based on all these parameters, of 4.1 mg/L.

/AQUATIC SPECIES/ ... The xylene isomers have a similar degree of toxicity as mixed xylenes to estuarine/marine invertebrates. For o-xylene, acute toxicity values range from the 96-hour embryo lethality EC50 value of 4.1 mg/L in sea urchin eggs ... to the 48-hour LC50 value of 24.7 mg/L in brine shrimp ... .[U.S. EPA Office of Prevention, Pesticides and Toxic Substances; Environmental Fate and Ecological Risk Assessment for the Reregistration of Xylene Range Aromatic Solvents p.39 (October 4, 2005) EPA Docket No. EPA HQ-OPP-2006-0145-0002

6.40e+02

2.80e+03

1.00e+02

4.40e+02

1.90e+02

2.00e+00

1.90e-01

2.00e-01

1.00e-01

Volatile

4.34e+02

1.90e+03

8.40e+03

3.10e+02

1.30e+03

5.80e+02

The substance is toxic to aquatic organisms.

2-Xylene's production and use in the manufacture of chemicals and in gasoline blending may result in its release to the environment through various waste streams. 2-Xylene may be released to the environment through emissions from various fuel industries and through evaporative emissions from fuels such as gasoline. It is emitted to air from burning wood and in motor vehicle exhaust. 2-Xylene occurs naturally in petroleum and coal tar, is released during forest fires and occurs in various plants. If released to air, a vapor pressure of 6.65 mm Hg at 25 °C indicates 2-xylene will exist solely as a vapor in the atmosphere. Vapor-phase 2-xylene will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and nitrate radicals; the half-lives for these reaction in air is estimated to be 1.2 and 85 days respectively. 2-Xylene has been detected in rainwater and snow and, therefore, it may be removed from the air by wet deposition. 2-Xylene does not absorb at wavelengths >290 nm and, therefore, is not expected to be susceptible to direct photolysis by sunlight. If released to soil, 2-xylene is expected to have very high to moderate mobility in soil based upon Koc values ranging from 24-251. Volatilization from moist soil surfaces is expected to be an important fate process based upon a Henry's Law constant of 5.18X10-3 atm-cu m/mole. 2-Xylene is expected to volatilize from dry soil surfaces based upon its vapor pressure. 2-Xylene biodegrades in soil under both aerobic and anaerobic conditions. Biodegradation is an important process in subsurface soils and groundwater where volatilization is hindered. Utilizing a standard test (manometric respirometry), 90-94% of the theoretical biodegradation was reached in 4 weeks indicating 2-xylene can be readily biodegradable. However, under anaerobic conditions, a long lag period may be required before degradation commences. If released into water, 2-xylene is not expected to adsorb to suspended solids and sediment based upon the Koc values. 2-Xylene is expected to biodegrade in water under aerobic conditions based on reported half-lives ranging from days to weeks. Volatilization from water surfaces is expected to be an important fate process based upon this compound's Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 3.2 hours and 4.1 days, respectively. A BCF of 14 in goldfish indicates that bioconcentration in aquatic organisms is low. 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 2-xylene may occur through inhalation and dermal contact with this compound at workplaces where 2-xylene is produced or used. Monitoring data indicate that the general population may be exposed to 2-xylene via inhalation of ambient air, ingestion of food and drinking water, and dermal contact with consumer products containing 2-xylene. Contact with xylene occurs from a variety of consumer products, including gasoline, paint, varnish, shellac, rust preventives, and cigarette smoke. (SRC)

2-Xylene occurs naturally in petroleum(1), is released during forest fires(2), and occurs in various plants(3). 2-Xylene occurs in the volatiles emitted from corn, alfalfa and cereal silage(4).

2-Xylene's production and use in the manufacture of phthalic anhydride, in vitamin and pharmaceutical synthesis, in the manufacture of dyes and insecticides(1) and in gasoline blending(2) may result in its release to the environment through various waste streams(SRC). 2-Xylene may be released to the environment through emissions from petroleum refining, coal tar and coal gas distillation, through emissions from the transport and storage of gasoline and from carburetors, and through leaks and evaporation losses during the transport and storage of gasoline and other fuels(2-4). 2-Xylene is emitted to air from burning wood(5) and in motor vehicle exhaust(6,7).

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values ranging from 24-251(2-5), indicate that 2-xylene is expected to have very high to moderate mobility in soil(SRC). Volatilization of 2-xylene from moist soil surfaces is expected to be an important fate process(SRC) given a Henry's Law constant of 5.18X10-3 atm-cu m/mole(6). 2-Xylene is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 6.65 mm Hg at 25 °C(7). 2-Xylene is expected to biodegrade in soil under both aerobic and anaerobic conditions(8). Biodegradation is an important process in subsurface soils and groundwater where volatilization is hindered(8). 2-Xylene has been observed to biodegrade in standard biodegradability tests using various inocula including sewage, activated sludge and sea water(9). For example, using aerobic OECD Guideline 301F (Ready Biodegradability: Manometric Respirometry Test) with a mixture of sewage, soil and natural water inoculum, 2-xylene reached 90-94% of its O2 consumption in 28 days which classified it as readily biodegradable in two separate studies(9). However, under anaerobic conditions, a long lag period may be required before degradation commences(10).

AQUATIC FATE: Based on a classification scheme(1), Koc values ranging from 24-251(2-5), indicates that 2-xylene is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(6) based upon a Henry's Law constant of 5.18X10-3 atm-cu m/mole(7). Using this Henry's Law constant and an estimation method(6), volatilization half-lives for a model river and model lake are 3.2 hours and 4.1 days, respectively(SRC). According to a classification scheme(8), a BCF of 14 measured in goldfish(9) indicates that bioconcentration in aquatic organisms is low(SRC). Biodegradation is an important process in groundwater where volatilization is hindered(10). 2-Xylene has been observed to biodegrade in standard biodegradability tests using various inocula including sewage, activated sludge and sea water(11). For example, using aerobic OECD Guideline 301F (Ready Biodegradability: Manometric Respirometry Test) with a mixture of sewage, soil and natural water inoculum, 2-xylene reached 90-94% of its O2 consumption in 28 days which classified it as readily biodegradable in two separate studies(11). Reported biodegradation half-lives in aerobic water range from days to weeks(12-15). However, under anaerobic conditions, a long lag period may be required before degradation commences(16). Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions(6).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2-xylene, which has a vapor pressure of 6.65 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 2-xylene 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 1.2 days(SRC), calculated from its rate constant of 1.36X10-11 cu cm/molecule-sec at 25 °C(3). Vapor-phase 2-xylene is also degraded in the atmosphere by reaction with night-time nitrate radicals(SRC); the half-life for this reaction in air is estimated to be 85 days(SRC), calculated from its rate constant of 3.77X10-16 cu cm/molecule-sec at 25 °C(4). 2-Xylene has been detected in rainwater and snow(5,6), and therefore, it may be removed from the air by wet deposition(SRC). 2-Xylene does not absorb at wavelengths >290 nm(7) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC).

AEROBIC: 2-Xylene has been observed to biodegrade in standard biodegradability tests using various inocula including sewage, activated sludge and sea water(1-4). It was completely degraded in 8 days in groundwater in a gasoline-oil mixture; the acclimation period was 3-4 days(5). In laboratory experiments designed to simulate saturated-flow conditions typical of a river water/ground water infiltration system, degradation was rapid with 70% removal in the first 1.5 cm of the column after 10 days of operation under aerobic conditions(6). Another investigator found that 2-xylene was readily biodegraded (33 mg/day loss) in shallow ground water in an unconfined sand aquifer when oxygen was present(7). As the available oxygen was consumed, the rate of degradation decreased(7). 2-Xylene degraded in two steps with adaptation periods of 14 and 49 days, using an unpolluted groundwater seed(8,9). Xylene (mixed isomers), present at 100 mg/L, reached 100% of its theoretical BOD in 4 weeks using an activated sludge inoculum at 30 mg/L in the Japanese MITI test which classified xylene as readily biodegradable(10). Using OECD Guideline 301F (Ready Biodegradability: Manometric Respirometry Test) with a mixture of sewage, soil and natural water inoculum, 2-xylene reached 90-94% of its O2 consumption in 28 days which classified xylene as readily biodegradable in two separate studies(11). An OECD Guideline 301F test using activated sludge found >60% degradation in 28 days, but degradation failed the 10-day window for being readily biodegradable(11).

AEROBIC: Aerobic microcosm studies, using aquifer soil and groundwater contacted by three different API PS-6 fuel blends (v/v), 85% gasoline and 15% methanol; 85% gasoline and 15% methyl-t-butyl ether; and 100% gasoline; with an acclimation period of less than one week, yielded half-lives of 14, 15, and 23 days, respectively, using an initial 2-xylene concentration of 228, 248, 168 ug/L, respectively(1). No degradation of 2-xylene was observed during the first 103 days of a microcosm study using a fourth fuel blend of 15% gasoline and 85% methanol and an initial 2-xylene concn of 544 ug/L. Limited oxygen microcosm studies, using aquifer soil and groundwater contacted by three different API PS-6 fuel blends (v/v), 85% gasoline and 15% methanol; 85% gasoline and 15% methyl-t-butyl ether; and 100% gasoline; with an aerobic period of less than three weeks for the gasoline with added oxygenates and less than one week for 100% gasoline, yielded biotransformation rates of 16, 14, and 20 ug/L-day, respectively, using an initial 2-xylene concentration of 575, 568, and 523 ug/L, respectively. No degradation of 2-xylene was observed in a limited oxygen microcosm study using a fourth fuel blend of 15% gasoline and 85% methanol and an initial 2-xylene concentration of 907 ug/L(1).

AEROBIC: A biodegradation study using contaminated aquifer solids and groundwater samples taken from a natural gas production site reported extensive removal of 2-xylene under natural aerobic conditions, no significant removal of 2-xylene under anaerobic conditions in the absence of nitrate or with added nitrate, and total inhibition of biodegradative activity when supplemented with hydrogen peroxide(1). Laboratory soil column studies operated under denitrifying conditions, at room temperature, indicate that 2-xylene was not degraded by acclimated indigenous soil microbiota (using soil samples from Niagara Falls, NY and Great Meadows, NJ)(2). Laboratory microcosm studies using aquifer material contaminated with aviation gasoline from the aerobic zone within the gasoline plume indicate that 2-xylene was degraded in the aerobic aquifer material(3).

ANAEROBIC: Degradation occurred anaerobically, but required denitrifying conditions and occurred only after the other xylene isomers had been removed(1). After six months lag, required for the microorganisms to establish the necessary enzymes for denitrification, biodegradation was rapid(1). 2-Xylene also degraded after a long lag period in a microcosm study that used anaerobic aquifer material from a site known to receive municipal landfill leachate and support methanogenesis(2). A lag period of >20 weeks was needed before there was any appreciable biodegradation, 78% and >99% degradation were reported at week 40 and 120, respectively(2). 2-Xylene was completely mineralized after a long adaptation period (200-255 days), under anaerobic conditions by aquifer-derived microorganisms obtained from creosote-contaminated sediment(3). Degradation was shown to be inhibited by the addition of preferred substrates (acetate, propionate, etc)(3). Laboratory microcosm studies using aquifer material contaminated with aviation gasoline from the anaerobic zone within the gasoline plume indicate that 2-xylene was degraded in the anaerobic aquifer material(4). 2-Xylene was degraded over 600 days in an anaerobic microcosm using sediment and groundwater from a polluted area(5).

The rate constant for the vapor-phase reaction of 2-xylene with photochemically-produced hydroxyl radicals is 1.36X10-12 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 1.2 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(2). The rate constant for the vapor-phase reaction of 2-xylene with night-time nitrate radicals is 3.77X10-16 cu cm/molecule-sec at 25 °C(3). This corresponds to an atmospheric half-life of about 85 days at an atmospheric concentration of 2.5X10+8 nitrate radicals per cu cm(4). The rate constant for the vapor-phase reaction of 2-xylene with ozone is 1.72X1-21 cu cm/molecule-sec at 25 °C(3). This corresponds to an atmospheric half-life of about 18 years at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(2). 2-Xylene is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(5). 2-Xylene, at 30 mg/L in water, does not absorb at wavelengths >290 nm(6) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC). Negligible absorption above 290 nm has also been reported for 2-xylene(7).

A log BCF of 1.15 (BCF of 14) was measured in goldfish(1) and a log BCF of 1.3 was measured in eels (Anguilla japonica)(2) for 2-xylene. According to a classification scheme(3), these BCF values indicate that bioconcentration in aquatic organisms is low(SRC). A log BCF value was measured in clams (log BCF of 0.79)(4). A log bioconcentration value of 2.3 ((ug/kg)/(ug/L)) was determined in a green alga, Selenastrium capricornutum(5).

Koc values measured for 2-xylene in various soils (% organic matter) were 24 in Wendover silty clay (16.2%), 26 in Vaudreil sand loam (10.0%), 68 in St. Thomas sand (3.1%), and 138 in Grimsby silt loam (1.0%)(1). Batch adsorption tests, using three solid sandy aquifer materials gave a Koc of 129(2). The Koc for 2-xylene in surface sediments collected from the central Tamar estuary in the UK was 25.4(3). The Koc values for 2-xylene in two river sediments (% organic matter 6.5-16.9 wt%) was 209 and 251, respectively(4). According to a classification scheme(5), these measured Koc values suggests that 2-xylene is expected to have very high to moderate mobility in soil. Using OECD Guideline 121 (estimating Koc via HPLC), the Koc of 2-xylene was estimated to be 537(6). Concentration enhancement has been observed for 2-xylene in a dune-infiltration project on the Rhine River(7); however, no 2-xylene reached groundwater under a rapid infiltration site(8). The log Koc for 2-xylene in coal sediment (% organic matter 52 wt%) was 2.40(4).

The Henry's Law constant for 2-xylene has been measured as 5.18X10-3 atm-cu m/mole(1). This Henry's Law constant indicates that 2-xylene is expected to volatilize rapidly from water surfaces(2). 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)(2) is estimated as 3.2 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)(2) is estimated as 4.1 days(SRC). 2-Xylene's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). 2-Xylene is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 6.65 mm Hg at 25 °C(3).

Generators of waste (equal to or greater than 100 kg/mo) containing this contaminant, EPA hazardous waste number U239 and F003, must conform with USEPA regulations in storage, transportation, treatment and disposal of waste.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Product: Contact a licensed professional waste disposal service to dispose of this material. Burn in a chemical incinerator equipped with an afterburner and scrubber but exert extra care in igniting as this material is highly flammable. Offer surplus and non-recyclable solutions to a licensed disposal company; Contaminated packaging: Dispose of as unused product.

/GUIDE 130 FLAMMABLE LIQUIDS (Non-Polar/Water-Immiscible/Noxious)/ 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. /Xylenes/

/GUIDE 130 FLAMMABLE LIQUIDS (Non-Polar/Water-Immiscible/Noxious)/ Health: May cause toxic effects if inhaled or absorbed through skin. Inhalation or contact with material may irritate or burn skin and eyes. Fire will produce irritating, corrosive and/or toxic gases. Vapors may cause dizziness or suffocation. Runoff from fire control or dilution water may cause pollution. /Xylenes/

/GUIDE 130 FLAMMABLE LIQUIDS (Non-Polar/Water-Immiscible/Noxious)/ Public Safety: CALL Emergency Response Telephone Number on Shipping Paper first. If Shipping Paper not available or no answer, refer to appropriate telephone number listed on the inside back cover. 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. /Xylenes/

/GUIDE 130 FLAMMABLE LIQUIDS (Non-Polar/Water-Immiscible/Noxious)/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Structural firefighters' protective clothing will only provide limited protection. /Xylenes/

For more DOT Emergency Guidelines (Complete) data for 2-XYLENE (8 total), please visit the HSDB record page.

UN 1307; Xylenes.

IMO 3; Xylenes

49 093 50; Xylenes

No person may /transport,/ offer or accept a hazardous material for transportation in commerce unless that person is registered in conformance ... and the hazardous material is properly classed, described, packaged, marked, labeled, and in condition for shipment as required or authorized by ... /the hazardous materials regulations (49 CFR 171-177)./

The International Air Transport Association (IATA) Dangerous Goods Regulations are published by the IATA Dangerous Goods Board pursuant to IATA Resolutions 618 and 619 and constitute a manual of industry carrier regulations to be followed by all IATA Member airlines when transporting hazardous materials. Xylenes is included on the dangerous goods list. /Xylenes/

The International Maritime Dangerous Goods Code lays down basic principles for transporting hazardous chemicals. Detailed recommendations for individual substances and a number of recommendations for good practice are included in the classes dealing with such substances. A general index of technical names has also been compiled. This index should always be consulted when attempting to locate the appropriate procedures to be used when shipping any substance or article. Xylenes is included on the dangerous goods list. /Xylenes/

Flammable Liquid

UN Hazard Class: 3; UN Pack Group: III