3,4-Dichlorophenyl isocyanate

188.01

188.01

608325

203-026-2

OZW0B7F1DU

76605

2250

DTXSID9033008

White to yellow crystals

29291090

29.4

3.88 (est)

Isocyanic acid, 3,4-dichlorophenyl ester is a white to yellow solid. Used as a chemical intermediate and in organic synthesis. (EPA, 1998)

1.4±0.1 g/cm3

43 °C

113 °C

>230 °F

1.575

Decomposes in water

Isocyanates are transported in railroad tank cars, tank trucks, tanks in ships, containers, and drums. They are stored in steel tanks and processed in steel equipment. For long-term storage stainless steel is recommended. To avoid contamination by atmospheric moisture, a dry air or inert gas blanket is essential. /Isocyanates/

0.2 mm Hg ( 20 °C)

Inhalation-rat LC50: 0.14 g/m3/2 hours; inhalation-mouse LC50: 0.14 g/m3/2 hours

Flammable; burning produces toxic chloride and nitrogen oxide gas

Henry's Law constant = 1.28X10-4 atm-cu m/mol at 25 °C (est)

Liquid Molar Volume = 0.1339 cu m/kmol|Hydroxyl radical reaction rate constant = 4.39X10-13 cu cm/molec-sec at 25 °C (est)

No rapid reaction with air. No rapid reaction with water.

Isocyanates and Isothiocyanates

Isocyanates and thioisocyanates, such as ISOCYANIC ACID, 3,4-DICHLOROPHENYL ESTER, are incompatible with many classes of compounds, reacting exothermically to release toxic gases. Reactions with amines, aldehydes, alcohols, alkali metals, ketones, mercaptans, strong oxidizers, hydrides, phenols, and peroxides can cause vigorous releases of heat. Acids and bases initiate polymerization reactions in these materials. Some isocyanates react with water to form amines and liberate carbon dioxide.

II

6.1

UN 2250 6.1/PG 2

2

23-36/37/38-42

22-26-36/37/39-45

NQ8760000

T

Treasury is ventilated, low temperature and dry; stored and transported separately from oxidants, acids and food

Stable under normal temperatures and pressures. Stable at room temperature in closed containers under normal storage and handling conditions.

P261-P280-P301 + P310-P305 + P351 + P338-P342 + P311

H301-H315-H317-H319-H332-H334-H335

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity 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 and plant life; and conformance with environmental and public health regulations.|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.

Inhalation of dust is poisonous; fire may produce irritating or poisonous gases. (EPA, 1998)

|Danger|H301 (100%): Toxic if swallowed [Danger Acute toxicity, oral]|P261, P264, P270, P271, P272, P280, P285, P301+P310, P302+P352, P304+P312, P304+P340, P304+P341, P305+P351+P338, P312, P321, P330, P332+P313, P333+P313, P337+P313, P342+P311, P362, P363, P403+P233, P405, and P501|Aggregated GHS information provided by 53 companies from 8 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.|H301: Toxic if swallowed [Danger Acute toxicity, oral]|P260, P261, P264, P270, P271, P280, P284, P301+P310, P304+P312, P304+P340, P305+P351+P338, P310, P312, P320, P321, P330, P403+P233, P405, and P501

Excerpt from ERG Guide 156 [Substances - Toxic and/or Corrosive (Combustible / Water-Sensitive)]: As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids. SPILL: Increase, in the downwind direction, as necessary, the isolation distance shown above. FIRE: If tank, rail car or tank truck 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, 2016)

Avoid inhalation of dust. Do not touch spilled material; stop leak if you can do so without risk. Small spills: absorb with sand or other noncombustible absorbent material and place into containers for later disposal. Small dry spills: with clean shovel place material into clean, dry container and cover; move containers from spill area. Large spills: dike far ahead of spill for later disposal. (EPA, 1998)

For emergency situations, wear a positive pressure, pressure-demand, full facepiece self-contained breathing apparatus (SCBA) or pressure- demand supplied air respirator with escape SCBA and a fully-encapsulating, chemical resistant suit. (EPA, 1998)|NIOSH investigators recommend that dermal exposures to isocyanate-containing substances be prevented. Employers should provide protective clothing, gloves, and footwear that is impervious to isocyanate--containing compounds. The protective clothing should either be disposed or laundered after each use (e.g., at the end of the work shift). The gloves should be elbow-length and made of an isocyanate-resistant material. /Isocyanate-containing substances/|Face-shields and aprons should be used whenever there is a possibility of a splash or a spill of liquids containing isocyanate-containing materials. /Isocyanate-containing substances/

Flammable liquid

If material on fire or involved in fire: Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not bur or burns with difficulty.) Use water in flooding quantities as fog. Use foam, dry chemical, or carbon dioxide. /Dichlorophenyl isocyanates/|Where there is a fire involving isocyanates, carbon dioxide or powder extinguishers must be employed. Firemen must be equipped with self-contained breathing apparatus. /Isocyanates/

Environmental considerations: Water spill: Use natural barriers or oil spill control booms to limit spill travel. Remove trapped material with suction hoses. /Dichlorophenyl isocyanates/|Environmental considerations: Land spill: Dig a pit, pond, lagoon, holding area to contain liquid or solid material. /SRP: If time permits, pits, ponds, lagoons, soak holes, or holding areas should be sealed with an impermeable flexible membrane liner./ Cover solids with a plastic sheet to prevent dissolving in rain or fire fighting water. /Dichlorophenyl isocyanates/|Decontamination of spilled isocyanates and disposal of isocyanate waste are best conducted by using aqueous ammonia (3-8% concentrated ammonia solution in 90-95% water with 0.2-5% liquid detergent) or aqueous sodium carbonate (5-10% sodium carbonate in 90-95% water and 0.2-5% liquid detergent). An alcoholic solution (50% ethanol, isopropyl alcohol, or butanol; 45% water; and 5% concentrated ammonia) may be preferred because of the low miscibility of isocyanates with water. /Isocyanates/

SRP: Contaminated protective clothing should be segregated in such a manner so 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.|SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits 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.|Personnel protection: avoid breathing fumes from burning material. Avoid breathing vapors or dusts. Avoid bodily contact with the material. ... Do not handle broken packages unless wearing appropriate personal protective equipment. Wash away any material which may have contacted the body with copious amounts of water or soap and water. /Dichlorophenyl isocyanates/|If material not on fire and not involved in fire: Keep sparks, flames, and other sources of ignition away. Build dikes to contain flow as necessary. /Dichlorophenyl isocyanates/|For more Preventive Measures (Complete) data for 3,4-DICHLOROPHENYL ISOCYANATE (7 total), please visit the HSDB record page.

/GUIDE 156: SUBSTANCES - TOXIC AND/OR CORROSIVE (COMBUSTIBLE/WATER-SENSITIVE)/ Fire or Explosion: Combustible material: may burn but does not ignite readily. Substance will react with water (some violently) releasing flammable, toxic or corrosive gases and runoff. When heated, vapors may form explosive mixtures with air: indoors, outdoors and sewers explosion hazards. Most vapors are heavier than air. They will spread along ground and collect in low or confined areas (sewers, basements, tanks). Vapors may travel to source of ignition and flash back. Contact with metals may evolve flammable hydrogen gas. Containers may explode when heated or if contaminated with water. /Dichlorophenyl isocyanates/|/GUIDE 156: SUBSTANCES - TOXIC AND/OR CORROSIVE (COMBUSTIBLE/WATER-SENSITIVE)/ Health: TOXIC; inhalation, ingestion or contact (skin, eyes) with vapors, dusts or substance may cause severe injury, burns or death. Contact with molten substance may cause severe burns to skin and eyes. Reaction with water or moist air will release toxic, corrosive or flammable gases. Reaction with water may generate much heat which will increase the concentration of fumes in the air. Fire will produce irritating, corrosive and/or toxic gases. Runoff from fire control or dilution water may be corrosive and/or toxic and cause pollution. /Dichlorophenyl isocyanates/|/GUIDE 156: SUBSTANCES - TOXIC AND/OR CORROSIVE (COMBUSTIBLE/WATER-SENSITIVE)/ Public Safety: CALL Emergency Response Telephone Number ... As an immediate precautionary measure, isolate spill or leak area in all directions for at least 50 meters (150 feet) for liquids and at least 25 meters (75 feet) for solids. Keep unauthorized personnel away. Stay upwind. Keep out of low areas. Ventilate enclosed areas. /Dichlorophenyl isocyanates/|/GUIDE 156: SUBSTANCES - TOXIC AND/OR CORROSIVE (COMBUSTIBLE/WATER-SENSITIVE)/ Protective Clothing: Wear positive pressure self-contained breathing apparatus (SCBA). Wear chemical protective clothing that is specifically recommended by the manufacturer. It may provide little or no thermal protection. Structural firefighters' protective clothing provides limited protection in fire situations ONLY; it is not effective in spill situations where direct contact with the substance is possible. /Dichlorophenyl isocyanates/|For more DOT Emergency Guidelines (Complete) data for 3,4-DICHLOROPHENYL ISOCYANATE (8 total), please visit the HSDB record page.

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.|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.

Strong irritant to tissue, especially eyes and mucous membranes.

Releases of CERCLA hazardous substances are subject to the release reporting requirement of CERCLA section 103, codified at 40 CFR part 302, in addition to the requirements of 40 CFR part 355. Isocyanic acid, 3,4-dichlorophenyl ester is an extremely hazardous substance (EHS) subject to reporting requirements when stored in amounts in excess of its threshold planning quantity (TPQ) of 500 or 10,000 lbs. Extremely hazardous substances that are solids are subject to either of two threshold planning quantities ... The lower quantity applies only if the solid exists in powdered form and has a particle size less than 100 microns; or is handled in solution or in molten form; or meets the criteria for a National Fire Protection Association (NFPA) rating of 2, 3 or 4 for reactivity. If the solid does not meet any of these criteria, it is subject to the upper ... threshold planning quantity ... .

3,4-Dichlorophenyl isocyanate was detected in effluent samples from 10 US wastewater treatment plants at a maximum concentration of 0.320 ug/L: overall, 72.5% frequency of detection, minimum 0.077 ug/L; maximum 0.32 ug/L; reporting level 0.5 ug/L(1).

most toxic

LD50 Rat oral 402 mg/kg bw|LD50 Rat ip 100 mg/kg bw|LD50 Rabbit dermal >2,000 mg/kg bw|LD50 Rat dermal >5,000 mg/kg bw|For more Non-Human Toxicity Values (Complete) data for 3,4-DICHLOROPHENYL ISOCYANATE (6 total), please visit the HSDB record page.

3,4-Dichlorophenyl isocyanate's production and use as a chemical intermediate in organic synthesis(1) may result in its release to the environment through various waste streams(SRC).

TERRESTRIAL FATE: If released to moist soil, isocyanic acid, p-chlorophenyl ester is not expected to leach or adsorb to solids nor volatilize due to its rapid hydrolysis(1). 3,4-Dichlorophenyl isocyanate is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 0.194 mm Hg at 25 °C(2). Biodegradation data in soil were not available(SRC, 2012).|AQUATIC FATE: Isocyanates hydrolyze readily in water to yield a carbamic acid, which decarboxylates to produce CO2 and an amine(1). Therefore, adsorption sediments, volatilization, and bioconcentration of 3,4-dichlorophenyl isocyanate are not expected to be important environmental fate processes in water(SRC). Biodegradation data in water were not available(SRC, 2012).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 3,4-dichlorophenyl isocyanate, which has an extrapolated vapor pressure of 8.0X10-2 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 3,4-dichlorophenyl isocyanate 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 24 days(SRC), calculated from its rate constant of 4.4X10-13 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(3). 3,4-Dichlorophenyl isocyanate does not contain chromophores that absorb at wavelengths >290 nm(4), and therefore is not expected to be susceptible to direct photolysis by sunlight(SRC).

The rate constant for the vapor-phase reaction of 3,4-dichlorophenyl isocyanate with photochemically-produced hydroxyl radicals has been estimated as 4.4X10-13 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 24 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Isocyanates hydrolyze readily in water to yield a carbamic acid, which decarboxylates to produce CO2 and an amine; the latter immediately reacts with more isocyanate to yield a disubstituted urea. The hydrolysis rate increases with electron-withdrawing substituents. Steric hindrance also influences hydrolysis rate; aliphatic isocyanate rates are: primary > secondary > tertiary(2). 3,4-Dichlorophenyl isocyanate does not contain chromophores that absorb at wavelengths >290 nm(3), and therefore is not expected to be susceptible to direct photolysis by sunlight(SRC).

Isocyanates hydrolyze readily in water to yield a carbamic acid, which decarboxylates to produce CO2 and an amine(1). Therefore, bioconcentration of 3,4-dichlorophenyl isocyanate is not expected to be important environmental fate processes in water(SRC).

Isocyanates hydrolyze readily in water to yield a carbamic acid, which decarboxylates to produce CO2 and an amine(1). Therefore, adsorption of 3,4-dichlorophenyl isocyanate to moist soils and sediments is not expected to be important environmental fate processes in water(SRC).

Isocyanates hydrolyze readily in water to yield a carbamic acid, which decarboxylates to produce CO2 and an amine(1). Therefore, volatilization of 3,4-dichlorophenyl isocyanate from water and moist soil surfaces is expected to be important environmental fate processes in water(SRC). 3,4-Dichlorophenyl isocyanate is expected to volatilize from dry soil surfaces(SRC) based upon an extrapolated vapor pressure of 0.08 mm Hg(2).

SURFACE WATER: 3,4-Dichlorophenyl isocyanate was detected in water samples at 10 US locations collected upstream from a wastewater treatment plant at a maximum concentration of 0.110 ug/L. Maximum concentrations in samples from two locations downstream were 0.230 and 0.280 ug/L(1).

Occupational exposure to 3,4-dichlorophenyl isocyanate may occur through inhalation of dust and dermal contact with this compound at workplaces where 3,4-dichlorophenyl isocyanate is produced or used. Limited monitoring data indicate that the general population may be exposed to 3,4-dichlorophenyl isocyanate via dermal contact with water containing 3,4-dichlorophenyl isocyanate. (SRC)

Strong irritant to tissue, especially eyes and mucous membranes (EPA, 1998)

Warning: Isocyanic acid, 3,4-dichlorophenyl ester is a strong irritant to tissue, especially eyes and mucous membranes. Caution is advised. Signs and Symptoms of Isocyanic Acid, 3,4-Dichlorophenyl Ester Exposure: Acute exposure to isocyanic acid, 3,4-dichlorophenyl ester may result in irritation and burning of the skin, eyes, and mucous membranes. Light-headedness, drowsiness, slurred speech, pupillary dilation, increased salivation, dysphagia (difficulty swallowing), abdominal pain, and spontaneous vomiting may occur. Stridor (high-pitched, noisy respirations), dyspnea (shortness of breath), and pulmonary edema are also common. Apathy and mental confusion may develop with possible progression to coma. Emergency Life-Support Procedures: Acute exposure to isocyanic acid, 3,4-dichlorophenyl ester may require decontamination and life support for the victims. Emergency personnel should wear protective clothing appropriate to the type and degree of contamination. Air-purifying or supplied-air respiratory equipment should also be worn, as necessary. Rescue vehicles should carry supplies such as plastic sheeting and disposable plastic bags to assist in preventing spread of contamination. Inhalation Exposure: 1. Move victims to fresh air. Emergency personnel should avoid self-exposure to isocyanic acid, 3,4-dichlorophenyl ester. 2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer 100% humidified oxygen or other respiratory support. 3. Obtain authorization and/or further instructions from the local hospital for performance of other invasive procedures. 4. Transport to a health care facility. Dermal/Eye Exposure: 1. Remove victims from exposure. Emergency personnel should avoid self-exposure to isocyanic acid, 3,4-dichlorophenyl ester. 2. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer 100% humidified oxygen or other respiratory support. 3. Remove and isolate contaminated clothing as soon as possible. 4. If eye exposure has occurred, eyes must be flushed with luke-warm water or sterile saline for at least 15 minutes. 5. Wash exposed skin areas thoroughly with water. 6. Obtain authorization and/or further instructions from the local hospital for performance of other invasive procedures. 7. Transport to a health care facility. Ingestion Exposure: 1. Evaluate vital signs including pulse and respiratory rate, and note any trauma. If no pulse is detected, provide CPR. If not breathing, provide artificial respiration. If breathing is labored, administer 100% humidified oxygen or other respiratory support. 2. DO NOT induce vomiting. 3. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures. 4. Activated charcoal is of no value. 5. Give the victims water: children up to 1 year old, 125 mL (4 oz or 1/2 cup); children 1 to 12 years old, 200 mL (6 oz or 3/4 cup); adults, 250 mL (8 oz or 1 cup). Water or milk should be given only if victims are conscious and alert. 6. Transport to a health care facility. (EPA, 1998)

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. /Isocyanates, aliphatic thiocyanates, 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 ... . Monitor for 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 patent can swallow, has a strong gag reflex, and does not drool. Administer activated charcoal ... . /Isocyanates, aliphatic thiocyanates, 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 /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. Consider vasopressors if patient is hypotensive with a normal fluid volume. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Isocyanates, aliphatic thiocyanates, and related compounds/|Emergency and supportive measures: After acute high-intensity inhalation exposure, maintain on open airway, give bronchodilators as needed for wheezing, and observe for 8-12 hours for pulmonary edema. Once airway hyperactivity has been documented, further exposure to isocyanate is contraindicated. Involve public health or OSHA agencies to determine whether other workers are at increased risk through improper workplace controls. /Isocyanates/|For more Antidote and Emergency Treatment (Complete) data for 3,4-DICHLOROPHENYL ISOCYANATE (6 total), please visit the HSDB record page.

/HUMAN EXPOSURE STUDIES/ Sera of six workers with conclusive evidence for IgE-mediated sensitization to isocyanates were used for evaluation of immunologic cross-reactivities among eight different isocyanate-protein conjugates. In all cases RAST and/or skin-test investigations revealed the presence of IgE antibodies reacting specifically with HSA conjugated with those isocyanates to which workers were exposed as well as with other isocyanates with which they had not been in contact. By the RAST inhibition technique, moderate to strong mutual cross-reactivities between all tested isocyanate-HSA conjugates--even between aromatic and aliphatic ones--could be demonstrated in tests with five sera. The magnitudes of cross-reactivities differed, however, from one patient to another. One serum contained IgE antibodies that were almost completely specific to TDI-HSA; with this serum only weak cross-reactivities with other isocyanate conjugates could be demonstrated. These results indicate the predominance of closely related antigenic determinants in HSA conjugated with different isocyanates. The common antibody-binding regions are obviously recognized to different extents by antibodies of clinically sensitized workers, indicating individual differences in specificities and avidities of antibody populations. Nearly complete lack of IgE binding of ovalbumin-bound TDI in RAST and RAST inhibition indicates carrier-specific antigenicity of isocyanate-protein conjugates. In addition, since unmodified HSA did not bind IgE, antigenic determinants of the conjugates studied should be predominantly formed by the isocyanate-protein bond regions and concurrently by neighboring amino acid residues of the HSA molecule. /Isocyanates/|/SIGNS AND SYMPTOMS/ Strong mucous membrane irritation causes eye, pulmonary, and gastrointestinal tract symptoms. These compounds are potent pulmonary sensitizers which cause bronchospasm, even in patients without prior airway hyperreactivity. Diisocyanate compounds act either as inducers of nonspecific bronchial hyperreactivity or as direct pharmacologic agonists. Isocyanates apparently have the potential to sensitize certain segments of the population. Elevated humoral antibodies (ie, specific IgE antibodies to the p-tolyl determinant but not the diisocyanate conjugate) were detected in sensitized workers, but cell-mediated immunity also may produce hypersensitivity reactions. In the absence of renewed exposure, radioallergosorbent titers may not distinguish sensitive from nonsensitized workers. At high doses, toluene diisocyanate may act directly on bronchial mucosa by interfering with cholinergic and adrenergic mechanisms. /Isocyanates/|/SIGNS AND SYMPTOMS/ Exposure to isocyanates is irritating to the skin, mucous membranes, eyes, and respiratory tract. The most common adverse health outcome associated with isocyanate exposure is asthma due to sensitization; less prevalent are contact dermatitis (both irritant and allergic forms) and hypersensitivity pneumonitis (HP). Contact dermatitis can result in symptoms such as rash, itching, hives, and swelling of the extremities. /Isocyanates/|/SIGNS AND SYMPTOMS/ A worker suspected of having isocyanate-induced asthma/sensitization will exhibit the traditional symptoms of acute airway obstruction, e.g., coughing, wheezing, shortness of breath, tightness in the chest, and nocturnal awakening. An isocyanate-exposed worker may first develop an asthmatic condition (i.e., become sensitized) after a single (acute) exposure, but sensitization usually takes a few months to several years of exposure. The asthmatic reaction may occur minutes after exposure (immediate), several hours after exposure (late), or a combination of both immediate and late components after exposure (dual). The late asthmatic reaction is the most common, occurring in approximately 40% of isocyanate sensitized workers. After sensitization, any exposure, even to levels below an occupational exposure limit or standard, can produce an asthmatic response that may be life threatening. Experience with isocyanates has shown that monomeric, prepolymeric and polyisocyanate species are capable of producing respiratory sensitization in exposed workers. /Isocyanates/|For more Human Toxicity Excerpts (Complete) data for 3,4-DICHLOROPHENYL ISOCYANATE (8 total), please visit the HSDB record page.

Benzene, 1,2-dichloro-4-isocyanato-: ACTIVE