Diamond	Hazard	Value	Description
4 4 3 W	Health	4	Can be lethal.
	Flammability	4	Burns readily. Rapidly or completely vaporizes at atmospheric pressure and normal ambient temperature.
	Instability	3	Capable of detonation or explosive decomposition or explosive reaction but requires a strong initiating source or must be heated under confinement before initiation.
	Special	W	Reacts violently or explosively with water.

Diborane is a colorless gas with an offensive odor. It is toxic by inhalation. Diborane is decomposed by water giving off hydrogen, another flammable gas and boric acid a non-regulated material. Its vapors are heavier than air. Long term exposure to low concentrations or short term exposure to high concentrations can result in adverse health effects from inhalation. It is used in electronics.

Rate of onset: Immediate

Persistence: Minutes to hours

Odor threshold: 2.5 ppm

Source/use/other hazard: Intermediate chemical manufacturing; very flammable.

• Strong Reducing Agent
• Water-Reactive
• Pyrophoric

Highly flammable. Ignites spontaneously in moist air (forms hydrogen and boric acid), [Haz. Chem. Data (1966)]. Oxygen and diborane form spontaneously explosive mixtures, [J. Amer. Chem. Soc. 76, 1997(1954)].

It will ignite spontaneously in moist air at room temperature. Also, it reacts violently with vaporizing liquid-type extinguishing agents. It hydrolyzes in water to hydrogen and boric acid. Incompatible with air, halogenated compounds, aluminum, lithium, active metals, oxidized surfaces, chlorine, fuming nitric acid, nitrogen trifluoride, oxygen, and phosphorus trifluoride. Avoid moist air, electrical sparks, open flames or any other heat source. Hazardous polymerization may occur. (EPA, 1998)

Boranes are highly toxic by inhalation, skin absorption or ingestion. They may produce acute or chronic poisoning. Diborane is an irritant to the lungs and kidneys. The primary effect of diborane poisoning is lung congestion caused by local tissue irritation produced by the exothermic reaction of hydrolysis. (EPA, 1998)

It is a colorless, air and moisture-sensitive gas, highly toxic. It ignites in air. It is very explosive when exposed to heat or flame, on contact with moisture it produces hydrogen gas. Explosive reaction with benzene vapor, chlorine, nitric acid and tetravinyllead [Bretherick, 5th ed., 1995, p. 77]. Explosive reaction with dimethyl sulfoxide [Shriver, 1969, p. 209], violent reaction with halocarbon liquids used as fire extinguishants (e.g., carbon tetrachloride). Reaction with Al or Li produces complex hydrides that may ignite spontaneously in air [Haz. Chem. Data, 1975, p. 114].

• Metal Hydrides, Metal Alkyls, Metal Aryls, and Silanes

No information available.

Excerpt from ERG Guide 119 [Gases - Toxic - Flammable]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 100 meters (330 feet) in all directions.

SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 1911 datasheet.

FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 1600 meters (1 mile) in all directions; also, consider initial evacuation for 1600 meters (1 mile) in all directions. (ERG, 2020)

Firefighting should be done from an explosion-resistant location. Use water from unmanned monitors or hose holders to keep fire-exposed containers cool. If it is necessary to stop flow of gas, use water spray to protect personnel effecting shut-off. Personnel should be evacuated immediately. Self-contained breathing apparatus and full protective clothing should be worn. Isolate for 1/2 mile in all directions if tank car or truck is involved in fire.

Inert gas substances such as liquid nitrogen are recommended as fire extinguishing agents. (EPA, 1998)

Excerpt from ERG Guide 119 [Gases - Toxic - Flammable]:

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. Do not direct water at spill or source of leak. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. FOR CHLOROSILANES, use AFFF alcohol-resistant medium-expansion foam to reduce vapors. If possible, turn leaking containers so that gas escapes rather than liquid. Prevent entry into waterways, sewers, basements or confined areas. Isolate area until gas has dispersed. (ERG, 2020)

Excerpt from NIOSH Pocket Guide for Diborane:

Skin: No recommendation is made specifying the need for personal protective equipment for the body.

Eyes: No recommendation is made specifying the need for eye protection.

Wash skin: No recommendation is made specifying the need for washing the substance from the skin (either immediately or at the end of the work shift).

Remove: No recommendation is made specifying the need for removing clothing that becomes wet or contaminated.

Change: No recommendation is made specifying the need for the worker to change clothing after the workshift. (NIOSH, 2023)

Normalized Breakthrough Times (in Minutes)

Chemical	CAS Number	State	QS	QC	SL	C3	TF	TP	RC	TK	RF
Diborane (10%)	19287-45-7	Vapor							>480	>480	>480

Special Warning from DuPont: Tychem® and Tyvek® fabrics should not be used around heat, flames, sparks or in potentially flammable or explosive environments. Only...

(DuPont, 2023)

Warning: Effects may be delayed up to 24 hours. Caution is advised.

Signs and Symptoms of Acute Diborane Exposure: Signs and symptoms of acute exposure to diborane may include tightness in the chest, dyspnea (shortness of breath), cough, and wheezing. Nausea and pulmonary edema may also occur. Other possible effects of acute exposure include dizziness, headache, weakness, lack of coordination, muscle spasms, tremor, and seizures. Exposure to diborane may irritate or burn the skin, eyes, and mucous membranes.

Emergency Life-Support Procedures: Acute exposure to diborane 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 diborane.
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 oxygen or other respiratory support.
3. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or 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 diborane.
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 oxygen or other respiratory support.
3. Remove contaminated clothing as soon as possible.
4. If eye exposure has occurred, eyes must be flushed with lukewarm water for at least 15 minutes.
5. Wash exposed skin areas at least twice with large amounts of cool water.
6. Obtain authorization and/or further instructions from the local hospital for administration of an antidote or performance of other invasive procedures.
7. Transport to a health care facility.

Ingestion Exposure: No information is available. (EPA, 1998)

• BORANE (B2H6)
• BOROETHANE
• BORON HYDRIDE
• BORON HYDRIDE (B2H6)
• DIBORANE
• DIBORANE (B2H6)
• DIBORANE(6)
• DIBORON HEXAHYDRIDE
• HYDROGEN BORIDE (H6B2)