M-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)

This chemical does not meet GHS hazard criteria for 0.8% (11 of 1386) of reports.

H226 (99.2%): Flammable liquid and vapor [Warning Flammable liquids]

H304 (41.8%): May be fatal if swallowed and enters airways [Danger Aspiration hazard]

H312+H332 (37.2%): Harmful in contact with skin or if inhaled [Warning Acute toxicity, dermal; acute toxicity, inhalation]

H312 (98.7%): Harmful in contact with skin [Warning Acute toxicity, dermal]

H315 (99.2%): Causes skin irritation [Warning Skin corrosion/irritation]

H318 (31.8%): Causes serious eye damage [Danger Serious eye damage/eye irritation]

H319 (10.5%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H332 (98.7%): Harmful if inhaled [Warning Acute toxicity, inhalation]

H335 (10.4%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

P210, P233, P240, P241, P242, P243, P261, P264, P264+P265, P271, P280, P301+P316, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P305+P354+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 1386 reports by companies from 24 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Reported as not meeting GHS hazard criteria per 11 of 1386 reports by companies.

There are 23 notifications provided by 1375 of 1386 reports by companies with hazard statement code(s).

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]

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

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

H401: Toxic 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]

P210, P233, P240, P241, P242, P243, P260, P261, P264, P264+P265, P270, P271, P273, P280, P301+P316, P302+P352, P303+P361+P353, P304+P340, P305+P351+P338, P308+P316, 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)

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

P203, P210, P233, P240, P241, P242, P243, P260, P261, P264, P264+P265, P270, P271, P280, P301+P316, 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)

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

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]

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)

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.

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: 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. Contact a licensed professional waste disposal service to dispose of this material; 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 3-XYLENE (8 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 away from oxidizers. STORE AWAY FROM SOURCES OF IGNITION. (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.

Protect containers against physical damage. Outdoor or detached storage is preferable. Indoor storage should be in a standard flammable liquid storage room.

Biological Exposure Indices (BEI) [ACGIH] - Xylenes (technical or commercial grades): 0.3 g/g creatine methylhippuric acids in urine at end of shift; [ACGIH TLVs and BEIs]

100.0 [ppm]

130 [ppm]

920 [ppm]

2500 [ppm]

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)

900.0 [ppm]

See: 95476

150.0 [ppm]

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 (L134)

Intermediate Inhalation: 0.6 ppm (L134)

Chronic Inhalation: 0.05 ppm (L134)

Acute Oral: 1 mg/kg/day (L134)

Intermediate Oral: 0.4 mg/kg/day (L134)

Chronic Oral: 0.2 mg/kg/day (L134)

DOE Protective Action Criteria (PAC): Temporary Emergency Exposure Limits (TEELs) for 3-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, skin and respiratory tract. 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 m-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 3-XYLENE (9 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

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

Colorless liquid; [Merck Index] Sweet odor; [CHRIS]

COLOURLESS LIQUID WITH CHARACTERISTIC ODOUR.

Colorless liquid with an aromatic odor.

Clear, colorless liquid

Color: Saybolt units +30 (research, pure and technical grades)

Sweet odor

Aromatic odor

Taste threshold: 0.3 ppm

282.4 °F at 760 mmHg (NTP, 1992)

139.1 °C

p-Xylene and m-xylene cannot be separated by distillation because their boiling points are too close.

139.07 °C @760 [mm Hg]

-54.2 °F (NTP, 1992)

-47.85 °C

-47.8 °C

85 °F (NTP, 1992)

25.0 °C (77.0 °F) - closed cup

77 °F (25 °C) (closed cup)

25 °C c.c.

Insoluble (NTP, 1992)

In water, 1.61X10+2 mg/L at 25 °C.

In water, 160 mg/L at 25 °C (average of 13 literature values ranging from 134-206 mg/L at 25 °C)

Miscible with acetone, alcohol, ether, benzene; soluble in chloroform

Solubility in water, g/l at 25 °C: 0.174 (very slightly soluble)

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

0.8698 g/cu cm at 25 °C

Critical density: 2.66 mmol/cu m; Critical volume: 376.0 cu m/mol

Relative density (water = 1): 0.86 (20 °C)

0.8598 @25 °C

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

3.66 (Air = 1)

Relative vapor density (air = 1): 3.7

10 mmHg at 82.9 °F (NTP, 1992)

8.29 [mmHg]

8.29 mm Hg at 25 °C

Vapor pressure, kPa at 20 °C: 0.8

7.5 [mm Hg] @23.4 °C

log Kow = 3.20

Henry's Law constant = 7.18X10-3 atm-cu m/mole at 25 °C

Highly flammable. Insoluble in water.

Hydrocarbons, Aromatic

Highly Flammable

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

Incompatible materials: Strong oxidizing agents.

Can react with oxidizing materials.

Strong oxidizers, strong acids.

Strong oxidizers, strong acids

IDENTIFICATION AND USE: 3-Xylene (m-xylene) is a clear colorless liquid. It is used as a solvent; intermediate for dyes and organic synthesis, especially isophthallic acid; in insecticides; in aviation fuel. m-Xylene is also used in the manufacturing of polyester and alkyl resins. HUMAN EXPOSURE AND TOXICITY: The effects of exposure to m-xylene on the central nervous system were investigated in humans. Male volunteers were exposed to m-xylene vapor, at stable concentration of 8.2 umol/L or fluctuating concentration with peaks (16.4 umol/L) for 4 hr a day. Body balance of subjects was clearly impaired in the anteroposterior direction, especially when subjects closed their eyes during the peaks at rest. Body balance improved when subjects exercised, even in the presence of the high m-xylene concn in the blood. Complex motor reactions were impaired after the peaks combined with exercise. In other experiment volunteers exposed to m-xylene were subjected to tests of numerical ability, reaction time, short-term memory and critical flicker fusion. There was evidence of reduction in the performance on 3 of the 4 tests in the second set of experiments. Slight, but statistically significant, increases in the average rating for subjective symptoms of neurological effects were observed following exposure to 50 ppm m-xylene vapor compared to controls. After 60 and 118 minutes of exposure, severity ratings for feelings of intoxication were elevated in men and women, and ratings for headache were elevated in men. The ratings for dizziness were increased in exposed men after 118 minutes of exposure. For biomonitoring purposes the m-and p-xylene isomers usually are measured together and reported as m/p-xylene. ANIMAL STUDIES: Exposure of rats to 2000 ppm of m-xylene for 3 days increased hepatic cytochrome P450 concentration and reduced nicotinamide adenine dinucleotide cytochrome c reductase activity. Adverse respiratory effects noted in rats, mice, and guinea pigs following acute and intermediate inhalation exposure to m-xylene are similar to those observed in humans. They include decreased respiration, labored breathing, irritation of the respiratory tract, pulmonary edema, pulmonary hemorrhage, and pulmonary inflammation. In a study of levels of noradrenaline and dopamine in various parts of the forebrain and hypothalamus, rats (six males/group) were exposed to 0 or 2000 ppm m-xylene, 6 hr/day for 3 days. The animals were killed within 18 hr after the last exposure. A significant increase in catecholamine levels and turnover was observed in various parts of the hypothalamus of exposed animals. There was no effect on dopamine levels. Histological damage to the outer hair cells of the organ of Corti provided evidence of ototoxicity in rats exposed by oral gavage to p-xylene, but not m- or o-xylene, at a dose of 900 mg/kg/day, 5 days/week for 2 weeks. No effect on absolute or relative heart weights was observed in male rats intermittently exposed to m-xylene at concentrations as high as 100 ppm for 13 weeks. Exposure of rats to 1 mg/L of m-xylene, 4 hr/day for 6 months caused inhibition of the phagocytic activity of leukocytes. Mice were exposed to m-xylene at 150, 1500, or 3000 mg/cu m, 24 hr/day from days 7-14 of gestation. Toxic effects were decreased weight of fetuses, decreased activity of succinic dehydrogenase, alkaline and acid phosphatase, and glucose 6-phosphatase. Also m-xylene changed characteristic features of functional maturity of the nephron, retardation of fetus was dose related. At highest dose level it increased preimplantation fetal losses, increased incidence of extra ribs and interfered with process of implantation. The o- and p- isomers appeared more hazardous to the offspring than did the m-isomer. Malformations (ie cleft palate) associated with mixed or individual isomers were primarily reported at maternally toxic doses. Each xylene isomer was administered to male rats intraperitoneally in 2 similar doses, 24 hours apart over a range of concentrations from 0, 0.12-0.75 mL/kg (105-650 mg/kg) and evaluated femoral bone marrow 30 hours after the first injection. No increase in micronucleated polychromatic erythrocytes was observed for any xylene isomer. In an Ames assay, m-xylene did not revert Salmonella typhimurium strains TA1535, TA1537, TA1538, TA98, & TA100, either with or without metabolic activation. ECOTOXICITY STUDIES: The xylene isomers have a similar degree of toxicity as mixed xylenes to estuarine/marine invertebrates. For m-xylene and p-xylene, the respective 48-hour LC50 values are 19.3 and 24.5 mg/L in brine shrimp, suggesting that the m-xylene and p-xylene isomers are slightly toxic to estuarine/marine invertebrates on an acute basis.

m-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.

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

Neurotoxin - Acute solvent syndrome

Occupational hepatotoxin - Secondary hepatotoxins: the potential for toxic effect in the occupational setting is based on cases of poisoning by human ingestion or animal experimentation.

ACGIH Carcinogen - Not Classifiable.

SURROGATE. See Xylenes

LC50 (rat) = 5,984 ppm/6hr

LD50: 1590 mg/kg (Oral, Rat) (T18)

LC50: 6350 ppm over 4 hours (Inhalation, Rat) (T21)

LD50: 1548 mg/kg (Intraperitoneal, Mouse) (T26)

LD50: 1700 mg/kg (Subcutaneous, Rat) (T26)

LD50: 6661 mg/kg/day (Oral, Rat) (L165)

LD50: 3228 mg/kg/day (Dermal, Rabbit) (L165)

LD50 Rat oral 5011 mg/kg bw

LD50 Rabbit dermal 14.1 mL/kg (12.1 g/kg)

LC50 Rat inhalation 5984 ppm (5796-6181 ppm) for 6 hr

LC50 Mouse inhalation 5267 ppm (5025-5490 ppm) for 6 hr

LC50 Mouse inhalation 5300 ppm for 6 hr exposure.

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.

Ingestion of ethanol (0.8 g/kg) prior to exposure to m-xylene (6.0 or 11.5 mmol/cu m) produced a marked alteration in xylene kinetics. Blood xylene level rose and urinary methylhippuric acid excretion decreased suggesting ethanol decreased metab clearance of xylene by about one-half.

Healthy male subjects were exposed at weekly intervals to m-xylene concn of 6 umol/L (145 ppm) and 11.5 umol/L (290 ppm) for 4 hr alone and in combination with prior ingestion of single doses of alcohol (0.8 g/kg). Body sway was recorded with a strain gauge transducer platform with the subject's eyes closed and open, and the eyes closed/open ratio, indicating the grade of visual compensation for body balance. Alcohol with xylene concn of 11.5 umol/L significantly incr the ratio, a finding suggesting an unexpected combined effect of xylene and alcohol, possibly of metabolic origin, on the human equilibrium system.

The metabolic interaction and disposition of methyl ethyl ketone and m-xylene after single or multiple inhalation exposures were studied in rats. Male Wistar-rats were exposed one for 6 hr to 300 ppm m-xylene or 600 ppm methyl ethyl ketone vapor alone or in combination. Other rats were exposed to 600 ppm methyl ethyl ketone and 300 ppm m-xylene, separately or together, daily for 7 days. They were then given a final exposure 18 hr later. The rats were killed 0.5 or 18 hr after the last exposure and the blood and perirenal fat /were taken and analyzed for xylene and MEK. The livers were/ removed and assayed for 7-ethoxycoumarin-O-deethylase, 7-ethoxyresorufin-O-deethylase, and 7-pentoxyresorufin-O-deethylase. Urine samples collected from other animals were analyzed for methyl-hippuric acid, 2,4-dimethylphenol, and thioethers. Blood m-xylene concentrations were slightly, significantly increased in rats exposed to the mixture compared to those exposed to xylene only. Blood methyl ethyl ketone concentrations were not significantly affected by xylene. Blood xylene concentrations were similar in rats given the single and multiple exposures. Perirenal fat m-xylene concn in rats exposed to the mixture were significantly higher than in those exposed to xylene alone 0.5 and 18 hr after exposure ended. Xylene concentrations were significantly lower after the multiple exposure than after the single exposure. Fat methyl ethyl ketone concentrations were also increased by coexposure to m-xylene. Methyl-hippuric acid excretion was decreased and 2,4-dimethylphenol excretion increased in rats exposed to the mixture relative to those exposed to m-xylene only. All m-xylene exposed rats showed sharp increase in urinary thioether excretion. Thioether excretion in controls. Multiple exposures to xylene significantly increased hepatic 7-ethoxycoumarin-O-deethylase, 7-ethoxyresorufin-O-deethylase, and 7-pentoxyresorufin-O-deethylase activity. Methyl ethyl ketone caused only a slight increase in activity of these enzymes. The combined exposures caused a synergistic increase in 7-pentoxyresorufin-O-deethylase activity and an additive increase in 7-ethoxyresorufin-O-deethylase and 7-ethoxycoumarin-O-deethylase activity. The authors conclude that methyl ethyl ketone inhibits the metabolism of xylene by suppressing side chain oxidation, but not oxidation of the aromatic ring.

The present study was undertaken to investigate the mechanism of toxicokinetic interaction between toluene and m-xylene in vivo in the male Sprague-Dawley rat by physiologically based toxicokinetic modeling. First, the metabolic constants (Vmax and Km) were determined for toluene and m-xylene individually by conducting a series of closed-chamber inhalation exposures of three rats to starting concn of 500 to 4000 ppm. The values of Km (toluene, 0.55 mg/L; m-xylene, 0.20 mg/L) and Vmax (toluene, 4.8 mg/hr/kg; m-xylene, 8.4 mg/hr/kg) were obtained following best visual fit of physiologically based toxicokinetic model simulations to experimental data. Then using the same experimental set-up, rats were exposed to three different mixtures of both solvents (500 ppm toluene + 1000 ppm m-xylene; 1000 ppm toluene + 1000 ppm m-xylene; 1000 ppm toluene + 500 ppm m-xylene). The data from the time course of chamber solvent concn were analyzed with a binary chemical mixture physiologically based toxicokinetic model that had four mechanistic hypotheses of metabolic interaction (i.e., no interaction, competitive inhibition, noncompetitive inhibition, and uncompetitive inhibition) quantitatively defined in the liver compartment. The validity of the various model descriptions was verified with open-chamber inhalation exposure data on toxicokinetics of toluene and m-xylene. Overall, the results of this combined experimental and modeling approach are consistent with a competitive metabolic inhibition between m-xylene and toluene in the rat.

For more Interactions (Complete) data for 3-XYLENE (15 total), please visit the HSDB record page.

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/

LC50; Species: Cancer magister (Crab) larvae-stage I; Concentration: 12 ppm for 96 hr /Conditions of bioassay not specified/

LC50; Species: Crangon franciscorum (Shrimp); Concentration: 3.7 ppm for 96 hr /Conditions of bioassay not specified/

LC100; Species: Tetrahymena pyriformis (Ciliate); Concentration: 3.77 mmole/L for 24 hr /Conditions of bioassay not specified/

EC50; Species: Pseudokirchneriella subcapitata (Green algae); Conditions: freshwater, static; Concentration: 4900 ug/L for 72 hr; Effect: growth, general /formulated product/

For more Ecotoxicity Values (Complete) data for 3-XYLENE (14 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. Both m-xylene and p-xylene induced significant decreases in the fertilization rate at concentrations above 10 mg/L. 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/ The acute toxicity of xylene isomers was evaluated in two studies using Selenastrum capricornutum, a green algae .... 72-hour EC50 values for growth inhibition ranging from 3.2 mg a.i./L for p-xylene to 4.9 mg a.i/L for m-xylene /were reported/. ... 8-day EC50 values for growth inhibition ranging from 3.9 mg/L for m-xylene to 4.4 mg/L for p-xylene /were reported/.[U.S. EPA Office of Prevention, Pesticides and Toxic Substances; Environmental Fate and Ecological Risk Assessment for the Reregistration of Xylene Range Aromatic Solvents 133 pp. (October 4, 2005) EPA Docket No. EPA HQ-OPP-2006-0145-0002

/AQUATIC SPECIES/ Results indicate that the three xylene isomers have similar toxicities to freshwater invertebrates. For o-xylene, acute toxicity values range from the 24-hour LC50 value of 1.0 mg a.i./L in Daphnia magna ... to the 48-hour LC50 value of >22.4 mg/L in the snail ... , indicating that the toxicity of xylene isomers ranges from slightly to highly toxic in freshwater invertebrates. For m-xylene, acute toxicity values range from the 24-hour LC50 value of 4.7 mg a.i./L in Daphnia magna ... to the 48-hour LC50 value of 9.6 mg a.i./L in Daphnia magna ... , indicating that m-xylene is moderately toxic to freshwater invertebrates.[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.38-9 (October 4, 2005) EPA Docket No. EPA HQ-OPP-2006-0145-0002

/AQUATIC SPECIES/ ... The xylene isomers have a similar degree of toxicity as mixed xylenes to estuarine/marine invertebrates. ... For m-xylene and p-xylene, the respective 48-hour LC50 values are 19.3 and 24.5 mg/L in brine shrimp ... , suggesting that the m-xylene and p-xylene isomers are slightly toxic to estuarine/marine invertebrates on an acute basis.[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

5.50e+02

2.40e+03

1.00e+02

4.40e+02

1.90e+02

2.00e+00

1.90e-01

2.00e-01

1.00e-01

Volatile

3.88e+02

1.60e+03

7.10e+03

3.10e+02

1.30e+03

5.80e+02

The substance is harmful to aquatic organisms.

3-Xylene's production and use as a solvent, intermediate for dyes and organic synthesis (especially isophthalic acid), in the manufacture of insecticides and in gasoline blending may result in its release to the environment through various waste streams. 3-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. 3-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 8.29 mm Hg at 25 °C indicates 3-xylene will exist solely as a vapor in the atmosphere. Vapor-phase 3-xylene 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 17 hours. 3-Xylene has been detected in rainwater and snow and, therefore, it may be removed from the air by wet deposition. 3-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, 3-xylene is expected to have moderate mobility based upon Koc values ranging from 166-275. Volatilization from moist soil surfaces is expected to be an important fate process based upon a Henry's Law constant of 7.18X10-3 atm-cu m/mole. 3-Xylene is expected to volatilize from dry soil surfaces based upon its vapor pressure. 3-Xylene biodegrades in soil and water 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), 98% of the theoretical biodegradation was reached in 4 weeks indicating 3-xylene can be readily biodegradable. However, under anaerobic conditions, a long lag period may be required before degradation commences. If released into water, 3-xylene is not expected to adsorb to suspended solids and sediment based upon the range of Koc values. Under anaerobic conditions, 3-xylene was biodegraded in aquifer studies within weeks to months. 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 3.1 hours and 4.1 days, respectively. A BCF of 14.8 in goldfish suggest the potential for 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. Photooxidation may have some importance in surface waters exposed to sunlight. Occupational exposure to 3-xylene may occur through inhalation and dermal contact with this compound at workplaces where 3-xylene is produced or used. Monitoring data indicate that the general population may be exposed to 3-xylene via inhalation of ambient air, ingestion of food and drinking water, and dermal contact with consumer products containing 3-xylene. Contact with xylene occurs from a variety of consumer products, including gasoline, paint, varnish, shellac, rust preventives, and cigarette smoke. (SRC)

3-Xylene (in combination with the other xylene isomers) occurs naturally in petroleum(1) and is released during forest fires(1,2). 3-Xylene occurs in various plants(3) and is emitted in volatile emissions from corn, alfalfa and cereal silage(4). Mixed xylenes are present in petroleum stocks and natural gas in small quantities(5).

3-Xylene's production and use as a solvent, intermediate for dyes and organic synthesis (especially isophthalic acid), in the manufacture of insecticides(1) and in gasoline blending(2) may result in its release to the environment through various waste streams(SRC). 3-Xylene may be released into the environment through emissions from petroleum refining, through the use of gasoline and diesel engines, and through leaks and evaporation losses during the transport and storage of gasoline and other fuels(2). 3-Xylene is a component of coal tar(2). 3-Xylene is emitted to air from burning wood(3) and in motor vehicle exhaust(4-6).

In a survey of 62 cars, present in exhaust of gasoline engines at 1.9 vol% of emitted hydrocarbons; in exhaust of diesel engines at 1.9% emitted hydrocarbons; in reciprocating gasoline engine at 1.3% of emitted hydrocarbons; and in rotary gasoline engine at 5.6% of emitted hydrocarbons. /m- and p-xylene/

TERRESTRIAL FATE: Based on a classification scheme(1), Koc values ranging from 166-275(2-4), indicate that 3-xylene is expected to have moderate mobility in soil(SRC). Volatilization of 3-xylene from moist soil surfaces is expected to be an important fate process(SRC) given a Henry's Law constant of 7.18X10-3 atm-cu m/mole(5). 3-Xylene is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 8.29 mm Hg at 25 °C(6). 3-Xylene is expected to biodegrade in soil under both aerobic and anaerobic conditions(7). Biodegradation is an important process in subsurface soils and groundwater where volatilization is hindered(7). 3-Xylene has been observed to biodegade in standard biodegradability tests using various inocula(8). For example, using OECD Guideline 301F (Ready Biodegradability: Manometric Respirometry Test) with a mixture of sewage, soil and natural water inoculum, 3-xylene reached 98% of its O2 consumption in 28 days which classified 3-xylene as readily biodegradable(8). 3-Xylene, present in soil samples contaminated with jet fuel, was completely degraded aerobically within 5 days(9), suggesting that biodegradation may be an important environmental fate process in soil(SRC). In anaerobic aquifer studies, 3-xylene was degraded, usually within several weeks(10). However, under anaerobic conditions, a long lag period may be required before xylene degradation commences(11).

AQUATIC FATE: Based on a classification scheme(1), Koc values ranging from 166-275(2-4), indicate that 3-xylene is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected(5) based upon a Henry's Law constant of 7.18X10-3 atm-cu m/mole(6). Using this Henry's Law constant and an estimation method(5), volatilization half-lives for a model river and model lake are 3.1 hours and 4.1 days, respectively(SRC). According to a classification scheme(7), a BCF of 14.8 measured in goldfish(8) suggest the potential for bioconcentration in aquatic organisms is low(SRC). Biodegradation is an important process in groundwater where volatilization is hindered(9). 3-Xylene has been observed to biodegade in standard biodegradability tests using various inocula(10). For example, using OECD Guideline 301F (Ready Biodegradability: Manometric Respirometry Test) with a mixture of sewage, soil and natural water inoculum, 3-xylene reached 98% of its O2 consumption in 28 days which classified 3-xylene as readily biodegradable(10). However, under anaerobic conditions, a long lag period may be required before xylene degradation commences(11). Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions(5). Irradiation studies using humic substances(12) suggest photooxidation may have some environmental importance in natural surface waters exposed to sunlight(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 3-xylene, which has a vapor pressure of 8.29 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 3-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 17 hours(SRC), calculated from its rate constant of 2.31X10-11 cu cm/molecule-sec at 25 °C(3). Vapor-phase 3-xylene is degraded slowly in the atmosphere by reaction with night-time nitrate radicals(SRC); the half-life for this reaction in air is estimated to be 138 days(SRC), calculated from its rate constant of 2.32X10-16 cu cm/molecule-sec at 25 °C(4). 3-Xylene has been detected in rainwater and snow(5,6) and, therefore, it may be removed from the air by wet deposition(SRC). 3-Xylene does not absorb at wavelengths >290 nm(7) and, therefore, is not expected to be susceptible to direct photolysis by sunlight(SRC).

AEROBIC: 3-Xylene is degraded in standard biodegradability tests using a variety of inocula including sewage, activated sludge and seawater(1-4). Using a respirometric test, 91.8% biodegradation of 3-xylene, initially at 100 mg/L, was measured in 13 days with a lag period of 2 days(5). Half-lives of >97 and 24 days were reported for the biodegradation of 3-xylene in Texas and Oklahoma aquifers, respectively(6). Up to 0.4 mM 3-xylene was rapidly mineralized to CO2 in a laboratory aquifer column operated under denitrifying conditions; the degradation rate constant under continuous flow conditions was >0.45/hr(7). 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(8). Using OECD Guideline 301F (Ready Biodegradability: Manometric Respirometry Test) with a mixture of sewage, soil and natural water inoculum, 3-xylene reached 98% of its O2 consumption in 28 days which classified 3-xylene as readily biodegradable(9).

3-Xylene in a gas-oil mixture was completely degraded within 8 days in groundwater with an acclimation period of 3-4 days(1). The aerobic biotransformation of PS-6 gasoline in groundwater with no oxygenates added (initial 3-xylene = 216 ug/L) and with 15% methyl-tert-butyl ether (initial 3-xylene = 361 ug/L) resulted in first order rate constants of 0.038 and 0.058/day, respectively, with an acclimation period of <7 days and a total incubation period of 232 days; complete biodegradation in these soil microcosm studies required approximately 115 days(2). The biotransformation of PS-6 gasoline in groundwater under initially aerobic (7-<21 days) followed by anaerobic conditions with no oxygenates added (initial 3-xylene = 800 ug/L) and with 15% methyl-tert-butyl ether (initial 3- xylene = 863 ug/L) resulted in zero-order rate constants of 63 and 44 ug/L/day (for the aerobic period of the experiment), respectively; biodegradation of 3-xylene in these soil microcosm studies was not complete within 420 days(2). Anaerobic aquifer microcosms from a methanogenic, leachate-impacted zone were spiked with 119-137.2 ug/L 3-xylene; under control, nitrate- and sulfate-amended conditions, losses of 7, 13, and 15%, respectively, were reported after 187 days incubation(3). In situ columns were packed with aquifer material from the anaerobic leachate-impacted North Bay, Ontario aquifer(3). In nitrate-amended and acetate-amended columns, 3-xylene was not degraded biotically, with a small amount of degradation due to abiotic mechanisms; however, in columns with added sulfate, 3-xylene was rapidly biodegraded within 10-50 days, depending on the site(3).

Aerobic flow-through aquifer column studies resulted in 80% removal of the 3-/4-xylene(1). Combined 3-/4-xylene concentrations were not significantly reduced within 42 days following the addition of nitrate to this column; however, anaerobic conditions in the nitrate-amended column resulted in about 50% removal of 3-/4-xylene after several months(1). Leachate containing 3-/4-xylene at 100 ug/L was significantly biodegraded under denitrifying conditions but not under either iron-reducing or methanogenic conditions(2). Anaerobic microcosms were constructed using aquifer sediment and groundwater from the Seal Beach Naval Weapons Station in CA which had been contaminated with gasoline(3). Following the loss of toluene, 3-/4-xylene was biodegraded completely by day 39 with a maximum rate of 4.1 ug/L-hr(3). Following the addition of nitrate, there was less complete removal of 3-/4-xylene however, the maximum removal rate was increased to 5.4 ug/L-hr(3). During biodegradation, methyl groups of 3-xylene were oxidized to carboxyls giving m-toluate followed by 2-hydroxy-5-oxohepta-2,4-dienoate(6). 3-Methylsalicylate was also reported as a metabolite from the biodegradation of 3-xylene(6). 3-Methylbenzyl fumaric acid and 3-methylbenzyl succinic acid(4) and 3-methylbenzoate and traces of 3-methylbenzaldehyde(7) were reported as metabolites from the biodegradation of 3-xylene under anaerobic conditions(4). Combined 3-/4-xylene was rapidly removed from aerobic strip-pit pond water (from coal mining) which had been amended with either nutrients or nutrients and sewage with less than 5% remaining after 12 days incubation; pond water alone required 43 days to reach 86% removal(5).

Combined 3-/4-xylene, initially at 5.53 ug/L, was greater than 78% biodegraded using both activated sludge and biological aerated filter reactors(1). Soil samples contaminated with jet fuel, containing 3-xylene at 0.067 ug/mL soil extract initially, contained 0 ug 3-xylene/ml soil extract after 5 days incubation(2). In non-acclimated aquifer material incubated with 10 mg/L radiolabeled 3-xylene under denitrifying conditions, approximately 20 and 78% of the solution radiolabel was distributed as nonvolatile products and CO2, respectively, by day 7(3). In acclimated aquifer material incubated with 5 mg/L radiolabeled 3-xylene under denitrifying conditions, approximately 3.4 and 94% of the solution radiolabel was distributed as nonvolatile products and CO2, respectively, by day 7(3). Biodegradation of 3-xylene did not occur in unamended aquifer material; however, the addition of nitrate allowed the degradation of 3-xylene within 25 days(4). Zero-order rate constants of >0.29 and 0.14 mg/L/day were reported in aquifer microcosms for 3-xylene in aerobic and nitrate-reducing conditions, respectively(5). Groundwater contaminated with combined 3-/4-xylene (at 1300 ug/L) was treated with both upflow aerated columns and rotating biological contactors with 98% removal in 37 days and 96% removal in 146 days, respectively(6). 98.1% of the combined 3- and 4-xylenes present initially were biodegraded in an activated sludge treatment plant(7).

ANAEROBIC: In situ anaerobic slug test experiments on a weathered gasoline plume showed biodegradation of 3-xylene under nitrate-reducing (100% degradation in 10 days) and sulfate-reducing conditions (100% degradation in 47 days)(1).

The rate constant for the vapor-phase reaction of 3-xylene with photochemically-produced hydroxyl radicals has been measured as 2.31X10-11 cu m/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 17 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(2). The rate constant for the vapor-phase reaction of 3-xylene with night-time nitrate radicals is 2.32X10-16 cu cm/molecule-sec at 25 °C(3). This corresponds to an atmospheric half-life of about 138 days at an atmospheric concentration of 2.5X10+8 nitrate radicals per cu cm(4). The rate constant for the vapor-phase reaction of 3-xylene with ozone is 8.48X10-22 cu cm/molecule-sec at 25 °C(3). This corresponds to an atmospheric half-life of about 37 years at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(2). 3-Xylene is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(5). 3-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). Products from the gas-phase reaction of nitrate radicals with 3-xylene were 3-methylbenzaldehyde and 3-methylbenzyl nitrate(8).

3-Xylene has an ozone formation potential, relative to ethene, of 27.3 during 0-2 days and 47.4 for 0-4 days; this suggests that this compound has a low to medium ability to produce ozone(1). In an ordinary Swedish environment and a high NOx environment, the ozone formation potential, relative to ethene, for 3-xylene are 47.4 and 88.4, respectively(1). 3-Xylene has a moderately high photochemical reactivity under smog conditions, higher than the other xylene isomers, with loss rates varying from 9-42% per hr(2,3,4,5). Under simulated atmospheric conditions, glyoxal, propanalone, and formaldehyde were formed as products from the degradation of 3-xylene(6). The photooxidation of 3-xylene results in the production of carbon monoxide, formaldehyde, glyoxal, methylglyoxal, 3-methylbenzyl nitrate, m-tolualdehyde, 4-nitro-3-xylene, 5-nitro-3-xylene, 2,6-dimethyl-p-benzoquinone, 2,4-dimethylphenol, 6-nitro-2,4-dimethylphenol, 2,6-dimethylphenol, 4-nitro-2,6-dimethylphenol at 6.1, 2.9, 3.1, 20.6, 1.1, 18.1, 1.5, 0.6, 13.8, 0.2, 11.7, 0.2, and 7.6 as % reacted carbon, respectively(7). Irradiation of wood smoke resulted in the degradation of 3-and 4-xylene, combined, from initial concentrations of 14, 40, and 12 ppb to 7, 19, and 3 ppb, respectively, in three experiments(8).

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: 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. Contact a licensed professional waste disposal service to dispose of this material; 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 3-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