Hexamethylene diisocyanate

Excerpt from ERG Guide 156 [Substances - Toxic and/or Corrosive (Combustible / Water-Sensitive)]:

Use powder, carbon dioxide.

Fresh air, rest. Artificial respiration may be needed. Refer immediately for medical attention.

Wear protective gloves when administering first aid. Remove contaminated clothes. Rinse skin with plenty of water or shower. Refer for medical attention .

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

Rinse mouth. Refer for medical attention .

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.

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.

General First Aid:

(General first aid procedures)

· Wear positive pressure self-contained breathing apparatus (SCBA).

Biological Exposure Indices (BEI) [ACGIH] - 1,6-Hexamethylene diamine in urine (with hydrolysis) = 15 ug/g creatinine at end of shift; [TLVs and BEIs]

0.005 [ppm]

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. Keep run-off water out of sewers and water sources.

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/

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/

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

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

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

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: 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.

Evacuate danger area! Consult an expert! Personal protection: complete protective clothing including self-contained breathing apparatus. Ventilation. 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.

From November 1979 to June 1987, 47 operations in paint manufacturing and application operations using polyurethane coatings were surveyed for hexamethylene diisocyanate and HDI-based polyisocyantes. In total, 457 hexamethylene diisocyanate samples, of varying concentration, were recovered from the 47 surveyed operations. Personal sampling of hexamethylene diisocyanate concentrations in air during spraying operations were all <10 ppb. During non-spraying operations, all concentrations were <5 ppb(1). Concentrations in personal samples of spray operators at the Keesler Air Force Base ranged from 0.017-0.02 mg/cu m(2).

Antidotes to cyanide poisoning include hydroxocobalamin and sodium nitrite, which release the cyanide from the cytochrome system, and rhodanase, which is an enzyme occurring naturally in mammals that combines serum cyanide with thiosulfate, producing comparatively harmless thiocyanate. Oxygen therapy can also be administered. (L97)

Immunological (Immune System), Respiratory (From the Nose to the Lungs)

Nervous

Eyes, skin, respiratory system

Exposure to high levels of cyanide for a short time harms the brain and heart and can even cause coma, seizures, apnea, cardiac arrest and death. Chronic inhalation of cyanide causes breathing difficulties, chest pain, vomiting, blood changes, headaches, and enlargement of the thyroid gland. Skin contact with cyanide salts can irritate and produce sores. (L96, L97)

TERRESTRIAL FATE: Hexamethylene diisocyanate reacts readily with water to form amines and polyureas(1,2); therefore, reaction with water will be the dominant fate process in moist soil and leaching of monomeric hexamethylene diisocyanate in soil should not be important(SRC). Hexamethylene diisocyanate is expected to volatilize from dry soil surfaces(SRC) based upon a vapor pressure of 0.05 mm Hg at 25 °C(5).

AQUATIC FATE: Hexamethylene diisocyanate is not likely to be found in waste water streams because of its reactivity with water and tendency to form amine or urea derivatives(1,2). Therefore, adsorption to suspended solids and sediment and volatilization from water are not expected to be important environmental fate processes(SRC). Since hexamethylene diisocyanate hydrolyzes to form amines and urea, there is very little chance that it will bioconcentrate as monomeric hexamethylene diisocyanate(3).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), hexamethylene diisocyanate, which has a vapor pressure of 0.5 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase hexamethylene diisocyanate 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 16 hours(SRC), calculated from its rate constant of 7.9X10-12 cu cm/molecule-sec at 25 °C(3). Since hexamethylene diisocyanate reacts readily with water(4), atmospheric degradation may occur through contact with clouds, fog or rain(SRC). Aliphatic isocyanates do not absorb light at wavelengths >290 nm(2), and therefore hexamethylene diisocyanate is not expected to be susceptible to direct photolysis by sunlight(SRC).

ATMOSPHERIC FATE: While in the atmosphere hexamethylene diisocyanate is expected to undergo photolysis /and/ hydroxyl radical oxidations ...

The substance can be absorbed into the body by inhalation of its aerosol or vapour and through the skin.

inhalation, ingestion, skin and/or eye contact

Oral (L96) ; inhalation (L96) ; dermal (L96)

Cyanide is an inhibitor of cytochrome c oxidase in the fourth complex of the electron transport chain (found in the membrane of the mitochondria of eukaryotic cells). It complexes with the ferric iron atom in this enzyme. The binding of cyanide to this cytochrome prevents transport of electrons from cytochrome c oxidase to oxygen. As a result, the electron transport chain is disrupted and the cell can no longer aerobically produce ATP for energy. Tissues that mainly depend on aerobic respiration, such as the central nervous system and the heart, are particularly affected. Cyanide is also known produce some of its toxic effects by binding to catalase, glutathione peroxidase, methemoglobin, hydroxocobalamin, phosphatase, tyrosinase, ascorbic acid oxidase, xanthine oxidase, succinic dehydrogenase, and Cu/Zn superoxide dismutase. Cyanide binds to the ferric ion of methemoglobin to form inactive cyanmethemoglobin. (L97)

Burning sensation. Cough. Sore throat. Laboured breathing. Shortness of breath.

MAY BE ABSORBED! Redness.

Redness. Pain. Swelling of the eyelids.

irritation eyes, skin, respiratory system; cough, dyspnea (breathing difficulty), bronchitis, wheezing, pulmonary edema, asthma; corneal damage, skin blisters

Cyanide poisoning is identified by rapid, deep breathing and shortness of breath, general weakness, giddiness, headaches, vertigo, confusion, convulsions/seizures and eventually loss of consciousness. (L96, L97)

Hexamethylene diisocyanate was detected at a total concentration of 0.068 g (total yield of 0.62 mg/kg hydrocarbons generated) in emissions generated from an automobile fire test using a 1998 coupe(1).

Hexamethylene diisocyanate can be released to the environment during spray applications of polymer paints containing residual amounts (0.5-1.0%) of monomeric hexamethylene diisocyanate.

1,6-Hexamethylene diisocyanate

Nervous

1 x 10 ^-5 mg/m^3

[40 CFR 716.120] Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. Hexane, 1,6-diisocyanato- is included on this list. Effective date: 6/1/87; Sunset date: 12/19/95.

Listed as a hazardous air pollutant (HAP) generally known or suspected to cause serious health problems. The Clean Air Act, as amended in 1990, directs EPA to set standards requiring major sources to sharply reduce routine emissions of toxic pollutants. EPA is required to establish and phase in specific performance based standards for all air emission sources that emit one or more of the listed pollutants. Hexamethylene diisocyanate is included on this list.

Persons in charge of vessels or facilities are required to notify the National Response Center (NRC) immediately, when there is a release of this designated hazardous substance, in an amount equal to or greater than its reportable quantity of 100 lb or 45.4 kg. The toll free number of the NRC is (800) 424-8802. The rule for determining when notification is required is stated in 40 CFR 302.4 (section IV. D.3.b).

One of the main uses of hexamethylene diisocyanate is as a polymerizing agent in polyurethane spray paint formulations and coatings (e.g., automobile paint).

Used as a cross-linking agent to manufacture dental materials, contact lenses, medical adsorbents, and polyurethanes; may be released during the spraying of polyurethane paints; Commonly used as a hardener in polyurethane automobile paints; [HSDB] Occupational asthma reported in a spray painter; [Malo] Used to make polyisocyanate products for curing agents in polyurethane paint systems (automobile, marine, industrial maintenance, and other high-performance coatings); [ACGIH]

Painting (Pigments, Binders, and Biocides) [Category: Paint]

Component of polyurethane elastomers, coatings

Chemical intermediate

HDI is used primarily onsite in the manufacture of higher molecular weight biuret polyisocyanate products that are used as curing agents in the formulation of polyurethane paint systems for automobile refinishing, marine coatings, industrial maintenance, and other high performance coating systems.

2023: 40,000,000 - <55,000,000 lb

This is a high volume chemical with production exceeding 1 million pounds annually in the U.S.

Hexane, 1,6-diisocyanato- is listed as a High Production Volume (HPV) chemical (65FR81686). Chemicals listed as HPV were produced in or imported into the U.S. in >1 million pounds in 1990 and/or 1994. The HPV list is based on the 1990 Inventory Update Rule. (IUR) (40 CFR part 710 subpart B; 51FR21438).

Production volumes for non-confidential chemicals reported under the Inventory Update Rule. [Table#5715]

Production volume for non-confidential chemicals reported under the 2006 Inventory Update Rule. Chemical: Hexane, 1,6-diisocyanato-. Aggregated National Production Volume: 50 to < 100 million pounds.

... Industrially made from the corresponding amine (hexamethylene diamine) ... by reaction with phosgene or by the carbamate route (reaction of the amine with urea and alcohol).

HDI can be produced by phosgenation of hexamethylene diamine and by a phosgene free process. In the phosgenation process HDI is produced continuously by reacting 1,6-hexamethylene diamine with phosgene in a solvent. The solvent and excess phosgene are recovered and returned to the production process.

In the phosgene free process HDI is produced continuously by reacting 1,6-hexamethylene diamine with urea and n-butanol. Ammonia, which is formed as a by-product of the urethanization step is removed by a thermal exhaust purification. Butanol is recovered and returned to the production process. The crude HDI product is purified by distillation. Production and processing to higher molecular compounds is carried out in closed systems.

The product is used in a "blocked" form in many applications.

HDI-BT

In recent years there has been an interest in isocyanate exposures associated with 2 component polyurethane paints, especially as related to the autobody industry. ...The most common isocyanate-bearing substances found in these paints are polyisocyanates based on HDI. Two forms of HDI-based polyisocyanates exist: an aliphatic form, which is biuret of HDI, and a ringed compound, which is HDI trimer.

All Other Chemical Product and Preparation Manufacturing

Hexane, 1,6-diisocyanato-: ACTIVE

HDI is not used as the monomer. It is industrially processed to polymers like, uretdiones, isocyanurates, and biurets. Furthermore HDI can be industrially processed with polyols to higher molecular weight adducts. These products typically contain up to 0.5 % residual monomer HDI.