1,2,4-trimethylbenzene

H226: Flammable liquid and vapor [Warning Flammable liquids]

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

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

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

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

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

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

This chemical does not meet GHS hazard criteria for 0.4% (13 of 3204) of reports.

H226 (99.6%): Flammable liquid and vapor [Warning Flammable liquids]

H304 (12.3%): May be fatal if swallowed and enters airways [Danger Aspiration hazard]

H315 (98.8%): Causes skin irritation [Warning Skin corrosion/irritation]

H319 (99.6%): Causes serious eye irritation [Warning Serious eye damage/eye irritation]

H332 (99.6%): Harmful if inhaled [Warning Acute toxicity, inhalation]

H335 (99.1%): May cause respiratory irritation [Warning Specific target organ toxicity, single exposure; Respiratory tract irritation]

H411 (98.9%): Toxic to aquatic life with long lasting effects [Hazardous to the aquatic environment, long-term hazard]

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

Aggregated GHS information provided per 3204 reports by companies from 57 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Reported as not meeting GHS hazard criteria per 13 of 3204 reports by companies.

There are 56 notifications provided by 3191 of 3204 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]

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

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]

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, P319, P321, P331, P332+P317, P337+P317, P362+P364, P370+P378, P391, P403+P233, P403+P235, P405, and P501 (click each P-code to see the statement)

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

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

Fresh air, rest. Refer for medical attention.

Rinse skin with plenty of water or shower.

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 .

Excerpt from NIOSH Pocket Guide for 1,2,4-Trimethylbenzene:

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 - If this chemical contacts the skin, wash the contaminated skin with soap and water.

Breathing: RESPIRATORY SUPPORT - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform artificial respiration. Keep the affected person warm and at rest. Get medical attention as soon as possible.

Swallow: MEDICAL ATTENTION IMMEDIATELY - If this chemical has been swallowed, get medical attention immediately. (NIOSH, 2024)

(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 - If this chemical contacts the skin, wash the contaminated skin with soap and water.

Breathing: Respiratory support

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

Excerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]:

CAUTION: The majority of these products have a very low flash point. Use of water spray when fighting fire may be inefficient. CAUTION: For mixtures containing alcohol or polar solvent, alcohol-resistant foam may be more effective.

SMALL FIRE: Dry chemical, CO2, water spray or regular foam. If regular foam is ineffective or unavailable, use alcohol-resistant foam.

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

FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. For petroleum crude oil, do not spray water directly into a breached tank car. This can lead to a dangerous boil over. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2024)

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

This chemical is a flammable liquid. Poisonous gases are produced in fire. Small fires: dry chemical, carbon dioxide, water spray, or alcohol-resistant foam. Large fires: water spray, fog, or alcohol foam. Move container from fire if you can do so without risk. Spray cooling water on containers that are exposed to flames until well after fire is out. For massive fire in cargo area, use unmanned hose holder or monitoring nozzles; if this is impossible, withdraw from area and let fire burn. Isolate for one-half mile in all directions if tank car or truck is involved in fire. Vapors are heavier than air and will collect in low areas. Vapors may travel long distances to ignition sources and flashback. Vapors in confined areas may explode when exposed to fire. Containers may explode in fire. Storage containers and parts of containers may rocket great distances, in many directions. If material or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters. Notify local health and fire officials and pollution control agencies. From a secure, explosion-proof location, use water spray to cool exposed containers. If cooling streams are ineffective (venting sound increases in volume and pitch, tank discolors, or shows any signs of deforming), withdraw immediately to a secure position. If employees are expected to fight fires, they must be trained and equipped in OSHA 1910.156. /Trimethyl benzenes/

Excerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]:

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. 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. Do NOT wash away into sewer. Do NOT let this chemical enter the environment.

Evacuate and restrict persons not wearing protective equipment from area of spill or leak until cleanup is complete. Remove all ignition sources. Establish forced ventilation to keep levels below explosive limit. Absorb liquids in vermiculite, dry sand, earth, peat, carbon, or similar material and deposit in sealed containers. Keep this chemical out of a confined space ... because of the possibility of an explosion ... It may be necessary to contain and dispose of this chemical as a hazardous waste. If material or contaminated runoff enters waterways, notify downstream users of potentially contaminated waters. Contact your Department of Environmental Protection or your regional office of the federal EPA for specific recommendations. If employees are required to clean up spills, they must be properly trained and equipped. OSHA 1910.120(q) may be applicable. /Trimethyl benzenes/

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

Incineration /SRP: with appropriate emission controls/. /Trimethyl benzenes/

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

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

Work clothing that becomes wet or significantly contaminated should be removed and replaced.

In case of contact with eyes, rinse immediately with plenty of water and seek medical advice.

Excerpt from ERG Guide 128 [Flammable Liquids (Water-Immiscible)]:

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

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

Fireproof. Separated from strong oxidants. Well closed. Keep in a well-ventilated room.

Prior to working with this chemical you should be trained on its proper handling and storage. Before entering a confined space where this chemical may be present, check to make sure that an explosive concentration does not exist. Trimethylbenzene must be stored to avoid contact with oxidizers (such as perchlorates, peroxides, permanganates, chlorates, and nitrates), and strong oxidizers (such as chlorine, bromine, and fluorine) since violent reactions occur. Store in tightly closed containers in a cool, well-ventilated area away from heat. Sources of ignition such as smoking and open flames are prohibited where this chemical is used, handled, or stored in a manner that could create a potential fire or explosion hazard. Metal containers involving the transfer of 5 gallons or more of this chemical should be grounded and bonded. Drums must be equipped with self-closing valves, pressure vacuum bungs, and flame arresters. Use only nonsparking tools and equipment, especially when opening and closing containers of this chemical. /Trimethyl benzenes/

STORAGE TANKS SHOULD BE MOUNDED TO CONFINE ESCAPING LIQUID & ESCAPE FROM PROCESS VESSELS SHOULD BE CONTROLLED IN SIMILAR MANNER BY SILLS @ DOORWAYS, DESIGN OF FLOORS, ETC. /TRIMETHYLBENZENES/

20.0 [ppm]

AEGL 1: Notable discomfort, irritation, or certain asymptomatic non-sensory effects. However, the effects are not disabling and are transient and reversible upon cessation of exposure (Unit: ppm)

AEGL 2: Irreversible or other serious, long-lasting adverse health effects or an impaired ability to escape (Unit: ppm)

AEGL 3: Life-threatening health effects or death (Unit: ppm)

NR = Not recommended due to insufficient data

AEGLs Status: Final

140 [ppm]

360 [ppm]

470 [ppm]

TWA 25 ppm (125 mg/m3)

none See Appendix G

See: IDLH INDEX

10.0 [ppm]

8 hr Time Weighted Avg (TWA): 25 ppm. /Trimethyl benzene (mixed isomers)/

Excursion Limit Recommendation: Excursions in worker exposure levels may exceed 3 times the TLV-TWA for no more than a total of 30 minutes during a work day, and under no circumstances should they exceed 5 times the TLV-TWA, provided that the TLV-TWA is not exceeded. /Trimethyl benzene (mixed isomers)/

100 mg/m

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

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.

The substance defats the skin, which may cause dryness or cracking. Repeated or prolonged inhalation may cause effects on the lungs. This may result in chronic bronchitis. The substance may have effects on the central nervous system and blood.

Excerpt from NIOSH Pocket Guide for 1,2,4-Trimethylbenzene:

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 OR CONTAMINATED - Work clothing that becomes wet or significantly contaminated should be removed and replaced.

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

Wear appropriate personal protective clothing to prevent skin contact.

Wear appropriate eye protection to prevent eye contact.

Important additional information about respirator selection

NO open flames, NO sparks and NO smoking. Above 44 °C use a closed system, ventilation and explosion-proof electrical equipment. Prevent build-up of electrostatic charges (e.g., by grounding).

PREVENT GENERATION OF MISTS!

Use ventilation, local exhaust or breathing protection.

Protective gloves.

Wear safety spectacles.

Do not eat, drink, or smoke during work.

1,2,4-trimethylbenzene appears as a liquid. Flash point near 130 °F. Less dense than water and insoluble in water. Vapors irritate eyes, throat, and nose. Used in dyes and pharmaceuticals.

Liquid; CBI; Gas Vapor

Colorless liquid; [HSDB]

COLOURLESS LIQUID WITH CHARACTERISTIC ODOUR.

Clear, colorless liquid with a distinctive, aromatic odor.

Clear, colorless liquid

Distinctive, aromatic odor

334.4 °F at 760 mmHg (USCG, 1999)

168.89 °C

169.38 °C @760 [mm Hg]

-47.2 °F (USCG, 1999)

-43.77 °C

Heat of fusion at melting point= 1.3192X10+7 J/kmol; Liquid Molar Volume= 0.137779 cu m/kmol.

-43.8 °C

111 °F (USCG, 1999)

112 °F (44 °C) (Closed cup)

44 °C c.c.

0.006 % (NIOSH, 2024)

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

In water, 57 mg/L at 25 °C

0.057 mg/mL at 25 °C

Solubility in water: very poor

0.889 (USCG, 1999) - Less dense than water; will float

0.8758 g/cu cm at 20 °C; 0.8718 g/cu cm at 25 °C

Relative density (water = 1): 0.88

0.8758 @ 20°C

4.15 (Air = 1)

Relative vapor density (air = 1): 4.1

4.9 mmHg (USCG, 1999)

2.1 [mmHg]

2.10 mm Hg at 25 °C

0.75 [mm Hg] @11 °C

(56 °F): 1 mmHg

log Kow = 3.78

Henry's Law constant = 6.16X10-3 atm-cu m/mol at 25 °C

932 °F (USCG, 1999)

932 °F (500 °C)

5194.8 kJ/mol at 25 °C

39.2 kJ/mol at boiling point

29.71 dyn/cm at 20 °C

Insoluble in water.

Hydrocarbons, Aromatic

1,2,4-TRIMETHYLBENZENE is incompatible with the following: Oxidizers, nitric acid (NIOSH, 2024).

Oxidizers (perchlorates, peroxides, permanganates, chlorates, nitrates), strong oxidizers (chlorine, bromine, fluorine), and nitric acid. /Trimethyl benzenes/

Oxidizers, nitric acid.

Oxidizers, nitric acid

1,2,4-Trimethylbenzene

Developmental

Hematologic

Respiratory

1 x 10 ^-2 mg/kg-day

4 x 10 ^-2 mg/kg-day

6 x 10 ^-2 mg/m^3

2 x 10 ^-1 mg/m^3

Volatile Organic Compound (VOC)

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

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

The substance can be absorbed into the body by inhalation.

inhalation, ingestion, skin and/or eye contact

Confusion. Cough. Dizziness. Drowsiness. Headache. Sore throat. Vomiting.

Redness. Dry skin.

Redness. Pain.

See Inhalation.

irritation eyes, skin, nose, throat, respiratory system; bronchitis; hypochromic anemia; headache, drowsiness, lassitude (weakness, exhaustion), dizziness, nausea, incoordination; vomiting, confusion; chemical pneumonitis (aspiration liquid)

Eyes, skin, respiratory system, central nervous system, blood

Neurotoxin - Acute solvent syndrome

ACGIH Carcinogen - Not Classifiable.

PDF Document

IRIS Current

LC50 (rat) = 18,000 mg/m3/4h

LD50 Rabbit dermal >3160 mg/kg bw

LC50 Rat inhalation >2000 ppm/48 hr

LD50 Rat (male, Wistar) oral 6.0 g/kg /98% Pseudocumene/

LD50 Rat (male, Charles River CD) oral 3550 mg/kg (3040-4130 mg/kg, 95% confidence limits)

LD50 Rat (female, Charles River CD) oral 3280 mg/kg (2720-3960 mg/kg, 95% confidence limits)

... The toxicokinetics of 124TMB was studied in nine male, healthy volunteers exposed to solvent vapors in an exposure chamber for 2 hr during a work load of 50 W. The subjects were exposed to 2 ppm (11 mg/cu m) of 124TMB during exposure to 300 mg/cu m of white spirit. The 124TMB isomer was analysed in blood, urine and exhaled air by gas chromatography. The DMHA metabolites of all three TMB isomers were analysed in urine by high-performance liquid chromatography. The results were compared with previously published exposures to 2 and 25 ppm (120 mg/cu m) of 124TMB vapor alone. ... Blood levels of 124TMB and excretion rates of 3,4-DMHA in urine were markedly elevated both during and after exposure to white spirit compared to the same exposure level of 124TMB alone. ... It appears that components in white spirit interfere with the metabolic elimination of 124TMB. This should be considered in biological exposure monitoring as well as in risk assessment.

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 as 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 ml 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. Consider drug therapy for pulmonary edema ... . 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 /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... .Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Aromatic hydrocarbons and related compounds/

/HUMAN EXPOSURE STUDIES/ The objective of this study was to compare the toxicokinetics of inhaled 1,2,4-trimethylbenzene (1,2,4-TMB) in man after exposure to white spirit with that observed after exposure to 1,2,4-TMB alone. ... The toxicokinetics were studied in 9 male, healthy volunteers exposed to solvent vapors in an exposure chamber for 2 hr during a work load of 50 W. The subjects were exposed to 11 mg/cu m of 1,2,4-TMB on two occasions; during exposure to 1,2,4-TMB vapor alone and during exposure to 300 mg/cu m of white spirit. ... Further the occurrence of acute effects was studied by means of a questionnaire. Irritation and central nervous system symptoms were recorded by ratings on a 100-mm visual analogue scale. ... No irritation or central nervous system effects were reported at these conditions.

/SIGNS AND SYMPTOMS/ ... Using paint thinner... containing more than 80% of ... mesitylene and pseudocumene, there were symptoms of disturbance of blood coagulation... and tendency to hematoma formation, with ...low level of thrombocytes and erythrocytes. Bronchitis ...headache, fatigue and drowsiness ...by 70% of workers exposed to high concentrations.

/SIGNS AND SYMPTOMS/ CNS depressant; respiratory irritant.

/SIGNS AND SYMPTOMS/ Irritating to eyes, respiratory system and skin.

For more Human Toxicity Excerpts (Complete) data for 1,2,4-TRIMETHYLBENZENE (12 total), please visit the HSDB record page.

/LABORATORY ANIMALS: Acute Exposure/ Not sensitizing /in/ guinea pig maximization test.

/LABORATORY ANIMALS: Acute Exposure/ Moderately irritating /to rabbit skin/.

EC50; Species: Daphnia magna (Water flea, age 4-6 days, 1.5 mm); Conditions: freshwater, static, 23 °C, pH 6-7, dissolved oxygen 5-9 mg/L; Concentration: 30 mmol/cu m for 48 hr (95% confidence interval: 13-69 mmol/cu m); Effect: intoxication, immobilization

LC50; Species: Artemia salina (Brine shrimp, nauplii); Conditions: saltwater, static, 20 °C; Concentration: 100 mmol/cu m for 24 hr /> or =97% purity/

LC50; Species: Elasmopus pectinicrus (Scud, adult); Conditions: saltwater, renewal, 23 °C, salinity 30 ppt; Concentration: 5230 ug/L for 24 hr (95% confidence interval: 4890-5620 ug/L)

LC50; Species: Elasmopus pectinicrus (Scud, adult); Conditions: saltwater, renewal, 23 °C, salinity 30 parts per thousand; Concentration: 4910 ug/L for 48 hr (95% confidence interval: 4500-5340 ug/L)

For more Ecotoxicity Values (Complete) data for 1,2,4-TRIMETHYLBENZENE (9 total), please visit the HSDB record page.

/AQUATIC SPECIES/ No stress was observed in Oncorhynchus mykiss (rainbow trout, fingerling) or Petromyzon marinus (sea lamprey, larvae) at 5 mg/L for 24 hours.

3.00e+02

1.80e+03

6.30e+01

2.60e+02

5.60e+01

5.00e+01

8.10e-02

1.00e-02

6.00e-02

Volatile

2.19e+02

9.10e+02

5.30e+03

1.90e+02

7.90e+02

1.70e+02

The substance is toxic to aquatic organisms. Bioaccumulation of this chemical may occur in fish.

1,2,4-Trimethylbenzene's production and use as an intermediate in the manufacture of trimellitic anhydride, dyes, pharmaceuticals, and pseudocumidine, and its chief industrial use as a solvent and paint thinner may result in its release to the environment through various waste streams. 1,2,4-Trimethylbenzene is released directly to the environment as a component of gasoline and as an emission from gasoline-powered vehicles, municipal waste-treatment plants, and coal-fired power stations. Trimethylbenzenes are found in coal tar, occur in some mineral oils and are formed during the processing of crude oil. If released to the atmosphere, 1,2,4-trimethylbenzene will exist solely in the vapor phase in the ambient atmosphere, based on a measured vapor pressure of 2.1 mm Hg at 25 °C. Vapor-phase 1,2,4-trimethylbenzene is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals and nitrate radicals with half-lives of about 12 hours and 6-30 days, respectively. 1,2,4-Trimethylbenzene does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight. If released to soil, a measured Koc value of 537 suggests that 1,2,4-trimethylbenzene will have low mobility in soil. Volatilization from moist and dry soil surfaces is expected to occur based on a measured Henry's Law constant of 6.16X10-3 atm-cu m/mole and the vapor pressure of this compound, respectively. Non-volatilized 1,2,4-trimethylbenzene may be subject to biodegradation under aerobic conditions; however, anaerobic aquifer microcosms showed little biodegradation in comparison to poisoned controls. If released to water, 1,2,4-trimethylbenzene is expected to adsorb to sediment or particulate matter based on its Koc value. Volatilization from water surfaces is expected to occur based on the Henry's Law constant. Estimated volatilization half-lives for a model river and model lake are 3 hours and 4 days, respectively. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions. BCF values of 31-275 suggest bioconcentration in aquatic organisms is moderate to high. Occupational exposure to 1,2,4-trimethylbenzene may occur through inhalation and dermal contact with this compound at workplaces where it is produced or used. The general population may be exposed to 1,2,4-trimethylbenzene via inhalation of ambient air, particularly in areas with heavy vehicular traffic, ingestion of food and drinking water, or dermal exposure to products such as gasoline which contain 1,2,4-trimethylbenzene. (SRC)

/1,2,4-Trimethylbenzene is/ found in coal tar ... occurring in some mineral oils /and is/ formed during the processing of crude oil

1,2,4-Trimethylbenzene's production and use as an intermediate in the manufacture of trimellitic anhydride, dyes, pharmaceuticals, and pseudocumidine(1), and its chief industrial use as a solvent and paint thinner(2) may result in its release to the environment through various waste streams(SRC). 1,2,4-Trimethylbenzene is released directly to the environment as a component of gasoline(3) and as an emission from gasoline-powered vehicles(4,5), municipal waste-treatment plants(6), and a coal-fired power station(7).

TERRESTRIAL FATE: Based on a recommended classification scheme(1), a Koc value of 537 measured in soil(2), indicates that 1,2,4-trimethylbenzene is expected to have low mobility in soil(SRC). Volatilization of 1,2,4-trimethylbenzene is expected to be important from moist soil surfaces(SRC) given a measured Henry's Law constant of 6.16X10-3 atm-cu m/mole(3) and from dry soil surfaces(SRC) based on a measured vapor pressure of 2.1 mm Hg at 25 °C(4). Complete removal of 1,2,4-trimethylbenzene from sterile sandy loam soil samples contaminated with jet fuel was reported within 5 days, probably due to evaporation(5). Non-volatilized 1,2,4-trimethylbenzene may be subject to biodegradation(SRC). 1,2,4-Trimethylbenzene was degraded within 7 days during a study of the aerobic microbial degradation of components of gas oil in aqueous solution; this was demonstrated while contaminated water percolated through an unsaturated soil column(6).

AQUATIC FATE: Based on a recommended classification scheme(1), a Koc value of 537 measured in soil(2), indicates that 1,2,4-trimethylbenzene is expected to adsorb to suspended solids and sediment in water(SRC). 1,2,4-Trimethylbenzene is expected to volatilize from water surfaces(3) based on a measured Henry's Law constant of 6.16X10-3 atm-cu m/mole(4). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are approximately 3 hours and 4 days, respectively(SRC). According to a classification scheme(5), BCF values of 31 to 275(6), measured in fish, suggest that bioconcentration in aquatic organisms is moderate to high(SRC). Biodegradation under aerobic conditions may be an important fate process for this compound in water although high concentrations of 1,2,4-trimethylbenzene may be toxic to the indigenous microbial population(6,7).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 1,2,4-trimethylbenzene, which has a measured vapor pressure of 2.10 mm Hg at 25 °C(2), will exist solely as a vapor in the ambient atmosphere. Vapor-phase 1,2,4-trimethylbenzene is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be about 12 hours(SRC), calculated from its rate constant of 3.25X10-11 cu cm/molecule-sec at 25 °C(3). 1,2,4-Trimethylbenzene also reacts with nitrate radicals in the atmosphere(4); the half-life for this reaction in air is estimated as 6-30 days(SRC), calculated from rate constants in the range of 5.4X10-16 to 2.70X10-15 cu cm/molecule-sec at 25 °C(4). 1,2,4-Trimethylbenzene does not contain chromophores that absorb at wavelengths >290 nm(5) and therefore is not expected to be susceptible to direct photolysis by sunlight(SRC).

AEROBIC: 1,2,4-Trimethylbenzene present at 100 mg/L, reached 4-18% of its theoretical BOD in 4 weeks using an activated sludge inoculum at 30 mg/L and the Japanese MITI test(1). Complete removal of 1,2,4-trimethylbenzene (at 0.068 ug/mL soil extract) from sandy loam soil samples contaminated with jet fuel was reported within 5 days; sterile samples with 1,2,4-trimethylbenzene at 0.057 ug/mL soil extract also showed complete removal of this compound within 5 days, probably by evaporation(2). 1,2,4-Trimethylbenzene at 1.2 mg/L was completely biodegraded in an aerobic aquifer microcosm in 8 days and in a nitrate-reducing aquifer microcosm within 21 days(3). Aquifer microcosms under anaerobic conditions showed litlle biodegradation in comparison to a poisoned control over a 100 day period(3). 1,2,4-Trimethylbenzene was biodegraded under denitrifying conditions in an aquifer microcosm (96% degradation in 13 days)(4). 1,2,4-Trimethylbenzene at 500 mg/L was inoculated with activated sludge from three different treatment plants; during the first 24 hours this compound was toxic to all three sludges(5). In longer aeration periods, 7.5 days, 1,2,4-trimethylbenzene was significantly biodegraded (oxygen uptake about 2000 mg/L)(5).

AEROBIC: The rate of biodegradation of 1,2,4-trimethylbenzene in seawater was described as fast(1); however, no quantitative data were provided(SRC). Dissolved air flotation effluent from a class B petroleum refinery contained 1,2,4-trimethylbenzene at 176 ng/g; greater than 99% removal was shown following activated sludge treatment and 45% removal following activated carbon treatment(2). Addition of secondary wastewater (containing 1,2,4-trimethylbenzene at 0.66 to 0.81 ug/L) into a rapid infiltration basin in Pheonix, AZ gave 52% removal between basin inflow and outflow(3); removal may have been through a combination of volatilization, sorption and biodegradation(3). Microcosms prepared with uncontaminated core material and incubated under anaerobic conditions with added nitrate showed complete biodegradation of 1,2,4-trimethylbenzene within 42-50 days(4). 1,2,4-Trimethylbenzene was considerably degraded within 7 days during a study of the aerobic microbial degradation of components of gas oil in aqueous solution; this was demonstrated while contaminated water percolated through an unsaturated soil column(5). Laboratory microcosms constructed with groundwater and core material from the North Bay, Ontario aquifer (1,2,4-trimethylbenzene at 111.6 ug/L) and incubated under anaerobic conditions showed very little loss of trimethylbenzene (initial concentration 111.6 ug/L; final concentration 101 ug/L) over 187 days; microcosms with added nitrate and acetylene (to inhibit the reduction of nitrous oxide) exhibited minimal denitrification activity(6). In situ soil columns in the North Bay site showed complete loss of 1,2,4-trimethylbenzene in sulfur-amended columns within 105 days and 23% loss within 105 days for nitrate-amended columns(6).

PURE CULTURE: Biodegradation products 3,4-dimethylbenzoic acid and 3,4-dimethylphenol were reported following the incubation of 1,2,4-trimethylbenzene with a pure culture of Pseudomonas(1).

The rate constant for the vapor-phase reaction of 1,2,4-trimethylbenzene with photochemically-produced hydroxyl radicals has been measured as 3.25X10-11 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 12 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). The rate constant for the vapor-phase reaction of 1,2,4-trimethylbenzene with nitrate radicals has been measured as 5.4X10-16 to 2.70X10-15 cu cm/molecule-sec at 25 °C(2). This corresponds to an atmospheric half-life of about 6-30 days at an atmospheric concentration of 5X10+8 nitrate radicals per cu cm(2). Yields of glyoxal, methylglyoxal, and biacetyl from the reaction of 1,2,4-trimethylbenzene with nitrate radicals at 25 °C account for approximately 60% of the overall nitrate radical reaction if it is assumed that the corresponding unsaturated 1,4-dicarbonyls are formed together with the alpha-dicarbonyls(3). The rate constant for the vapor-phase reaction of 1,2,4-trimethylbenzene with ozone has been measured as 0.13X10-20 cu cm/molecule-sec at 24 °C(4). This corresponds to an atmospheric half-life of about 24 years(SRC) at an atmospheric concentration of 7X10+11 ozone molecules per cu cm(4). 1,2,4-Trimethylbenzene was reported as a precursor of peroxyacyl nitrates(5). 1,2,4-Trimethylbenzene and other components of jet fuels were lost when jet fuel/water mixture (1:1000) were exposed to sunlight in deionized water, artificial seawater, and pond water(6). The authors concluded that experimental errors and volatilization likely accounted for the loss since the water soluble components of these fuels, including 1,2,4-trimethylbenzene do not absorb ultraviolet light in the solar region(6). 1,2,4-Trimethylbenzene is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(7).

BCF values of 33-275 and 31-207 were measured in carp exposed to 1,2,4-trimethylbenzene at concentrations of 0.2 and 0.02 mg/L, respectively(1). According to a classification scheme(2), these BCF values suggest that bioconcentration in aquatic organisms is moderate to high, provided the compound is not metabolized by the organism(SRC).

A Koc value of 537 was measured for 1,2,4-trimethylbenzene in a German soil (80.5% sand 12.3% silt, 7.2% clay, 2.48% organic carbon). According to a suggested classification scheme(2), this Koc value suggests that 1,2,4-trimethylbenzene will have low mobility in soil(SRC).

The Henry's Law constant for 1,2,4-trimethylbenzene was measured as 6.16X10-3 atm-cu m/mol(1). This value indicates that 1,2,4-trimethylbenzene will volatilize from moist soil and water surfaces(2). Based on this Henry's Law constant, the estimated volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(2) is approximately 3 hours(SRC). The estimated volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(2) is approximately 4 days(SRC). Volatilization of 1,2,4-trimethylbenzene from dry soil surfaces is expected(SRC) based upon its vapor pressure of 2.1 mm Hg(3).

Complete removal of 1,2,4-trimethylbenzene (at 0.068 ug/mL soil extract) from sandy loam soil samples contaminated with jet fuel was reported within 5 days; sterile samples with 1,2,4-trimethylbenzene at 0.057 ug/mL soil extract also showed complete removal of this compound within 5 days, probably through evaporation(1). Jet fuel added to water (and then stirred) had an average volatilization ratio (volatilization rate constant of the compound/oxygen reaeration rate constant) of 0.59 for JP-4 fuel and a ratio of 0.45 for JP-8 fuel for the 1,2,4-trimethylbenzene component, indicating high volatility of this compound from water(2).

GROUNDWATER: Groundwater from 3 of 5 landfill sites in southern Ontario contained 1,2,4-trimethylbenzene at concentrations of 51, 53, and 14 ug/L for the Hamilton, North Bay, and New Borden sites, respectively(1). Following a leak of an underground gasoline storage tank, 1,2,4-trimethylbenzene was measured in groundwater at a concentration of 1.73 mg/L(2). Groundwater (from the Chalk aquifer, England) beneath a gasoline service station contained 1,2,4-trimethylbenzene at 1530 ug/l; the public water supply well (same aquifer) contained this compound at 0.13 ug/L(3). 1,2,4-Trimethylbenzene was detected in groundwater from two aquifers near an underground coal gasification experiment in northeastern Wyoming at concentrations from 88-460 ppb(4).

DRINKING WATER: 1,2,4-Trimethylbenzene was reported in drinking water stored in reservoirs made of concrete and coated with rubber(1). 1,2,4-Trimethylbenzene was detected in Cincinnati, OH drinking water (in February 1980) at 127 ng/L(2). 1,2,4-Trimethylbenzene was detected in tap water from Kitakyushu, Japan at a concentration of 3.3 ppb(3). Drinking water samples collected in 1976 from New Orleans, LA, Philadelphia, PA, Ottumwa, IO and Seattle, WA contained 1,2,4-trimethylbenzene at unreported concentrations(4).

SURFACE WATER: Seawater collected from the Baltic Sea, the English Channel, the Bay of Biscay, the coastal waters off Portugal, and the open Atlantic contained 1,2,4-trimethylbenzene at unreported concentrations(1). 1,2,4-Trimethylbenzene was measured in seawater collected from Vineyard Sound, MA over a 15 month period at concentrations of 2.2 to 25 ng/L(2). Water samples collected from the Southern North Sea during August 1983-July 1984 contained trimethylbenzenes at a mean concentration of 3 ng/L(3). 1,2,4-Trimethylbenzene was detected in water from the Besos and Llobregat Rivers in Spain(4). 1,2,4-Trimethylbenzene is a major contaminant in the Narragansett Bay, Rhode Island(5). 1,2,4-Trimethylbenzene was identified in water samples from the River Glatt, Switzerland at unreported concentrations(6).

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

Incineration /SRP: with appropriate emission controls/. /Trimethyl benzenes/

49 131 61; Pseudocumene

This compound requires a shipping label of: "Flammable Liquid, Poison." It falls in DOT Hazard Class 3 and Packing Group III. /Trimethyl benzenes/

Flammable Liquid

Symbol: Xn, N; R: 10-20-36/37/38-51/53; S: (2)-26-61

UN Hazard Class: 3; UN Pack Group: III