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Chemical Datasheet

METHYL BROMIDE

2.3 - Poisonous gas

Chemical Identifiers

CAS Number UN/NA Number DOT Hazard Label USCG CHRIS Code
  • 74-83-9   (METHYL BROMIDE)
  • 1062
  • Poison Gas
  • MTB
NIOSH Pocket Guide International Chem Safety Card
Methyl bromide
  • METHYL BROMIDE
NFPA 704
Diamond Hazard Value Description
1
3 0
Blue Health 3 Can cause serious or permanent injury.
Red Flammability 1 Must be preheated before ignition can occur.
Yellow Instability 0 Normally stable, even under fire conditions.
White Special
(NFPA, 2010)
General Description
Colorless highly toxic volatile liquid or a gas. Boiling point 3.56°C (38.41°F). Usually odorless, but has a sweetish chloroform-like odor at high concentrations. Used as an insecticide, a rodenticide, a fumigant, a nematocide, a chemical intermediate and as a fire extinguishing agent. (EPA, 1998)

Hazards

Reactivity Alerts
none
Air & Water Reactions
Nonflammable over a wide range of concentrations in air. Slightly soluble in water (about 1.75 g/100 mL of solution at 20°C). Reacts slowly with water to give methyl alcohol and hydrobromic acid. [Kirk-Othmer Vol. 4].
Fire Hazard
When heated to decomposition, it emits toxic fumes of bromides. Hazardous polymerization may not occur. (EPA, 1998)
Health Hazard
Methyl bromide is a dangerous cumulative poison with delayed symptoms of central nervous system intoxication that may appear as long as several months after exposure. High concentrations can produce fatal pulmonary edema. Chronic exposure can cause central nervous system depression and kidney injury. It may cause severe and permanent brain damage. Severe neurological signs may appear when there is a sudden exposure to high concentrations following continuous slight exposure. Methyl bromide has practically no odor or irritating effects and therefore no warning, even at hazardous concentrations. (EPA, 1998)
Reactivity Profile
METHYL BROMIDE is incompatible with metals, dimethyl sulfoxide, ethylene oxide. [Lewis]. Can give flammable products if mixed with potassium hydroxide, sodium hydroxide and other strong bases. Methyl bromide in a steel tank reacted with an aluminum tube (part of the level gauge) producing methyl aluminum bromide. When the latter was subsequently exposed to air, enough heat was produced to ignite the methyl bromide-compressed air mixture above the liquid layer. The ensuing explosion shattered the tank (also incompatible with zinc, magnesium, and alloys)[Chem. Eng. Pro. 58(8). 1962]. A reaction between methyl bromide and dimethyl sulfoxide resulted in an explosion that shattered the apparatus [NFPA 491M. 1991].
Belongs to the Following Reactive Group(s)
Potentially Incompatible Absorbents

No information available.

Response Recommendations

Isolation and Evacuation
Excerpt from ERG Guide 123 [Gases - Toxic]:

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 1062 datasheet.

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)
Firefighting
Full protective clothing, including self-contained breathing apparatus, coat, pants, gloves, boots, and bands around legs, arms, and waist should be provided. No skin surface should be exposed. Move container from fire area if you can do it without risk. Fight fire from maximum distance. Dike fire control water for later disposal; do not scatter the material.

Non-flammable in air; burns in oxygen. Use water spray, foam, carbon dioxide, or dry chemical. (EPA, 1998)
Non-Fire Response
Remove all ignition sources. Ventilate area of spill or leak, stop flow of gas or remove leaking cylinder to open air and repair leak or allow cylinder to empty. If material is in the liquid form, allow it to vaporize. Stay upwind, keep out of low areas. Use water spray to reduce vapors. (EPA, 1998)
Protective Clothing
Excerpt from NIOSH Pocket Guide for Methyl bromide:

Skin: PREVENT SKIN CONTACT (LIQUID) - If this chemical is in liquid form, wear appropriate personal protective clothing to prevent skin contact.

Eyes: PREVENT EYE CONTACT (LIQUID) - If this chemical is in liquid form, wear appropriate eye protection to prevent eye contact.

Wash skin: WHEN CONTAMINATED (LIQUID) - If this chemical is in liquid form, the worker should immediately wash the skin when it becomes contaminated.

Remove: WHEN WET (FLAMMABLE) - Work clothing that becomes wet should be immediately removed due to its flammability hazard (i.e., for liquids with a flash point <100°F).

Change: No recommendation is made specifying the need for the worker to change clothing after the workshift.

Provide: QUICK DRENCH (LIQUID) - Facilities for quickly drenching the body should be provided (when this chemical is in liquid form) within the immediate work area for emergency use where there is a possibility of exposure. [Note: It is intended that these facilities provide a sufficient quantity or flow of water to quickly remove the substance from any body areas likely to be exposed. The actual determination of what constitutes an adequate quick drench facility depends on the specific circumstances. In certain instances, a deluge shower should be readily available, whereas in others, the availability of water from a sink or hose could be considered adequate.] (NIOSH, 2024)
DuPont Tychem® Suit Fabrics
Normalized Breakthrough Times (in Minutes)
Chemical CAS Number State QS QC SL C3 TF TP RC TK RF
Bromo methane 74-83-9 Vapor >480 >480 >480 >480
Methyl bromide 74-83-9 Vapor >480 >480 >480 >480
> indicates greater than.

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, 2024)

First Aid
Warning: Effects may be delayed for hours to days. Caution is advised.

Signs and Symptoms of Acute Methyl Bromide Exposure: Signs and symptoms of acute exposure to methyl bromide may be severe and include tremors, convulsions, brain hemorrhage, paralysis, coma, and permanent brain damage. Respiratory effects include cough, tachypnea (rapid respiratory rate), pulmonary edema, and respiratory collapse. Cyanosis (blue tint to the skin and mucous membranes), pallor, ventricular fibrillation, and circulatory collapse may also occur. Lethargy, profound weakness, headache, dizziness, mental confusion, slurring of speech, staggering gait, and blurred or double vision are often found. Gastrointestinal signs and symptoms include nausea, vomiting, abdominal pain, and anorexia. Oliguria (scanty urination), anuria (lack of urine formation), kidney hemorrhage, and kidney failure may occur. Contact with methyl bromide may cause dermatitis (red, inflamed skin) and conjunctivitis (red, inflamed eyes).

Emergency Life-Support Procedures: Acute exposure to methyl bromide 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 methyl bromide.
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 methyl bromide.
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 twice with soap and 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)

Physical Properties

Chemical Formula:
  • CH3Br
Flash Point: None (EPA, 1998)
Lower Explosive Limit (LEL): 10 % (EPA, 1998)
Upper Explosive Limit (UEL): 16 % (EPA, 1998)
Autoignition Temperature: 999°F (USCG, 1999)
Melting Point: -136°F (EPA, 1998)
Vapor Pressure: 1420 mmHg at 68°F (EPA, 1998)
Vapor Density (Relative to Air): 3.27 (EPA, 1998) - Heavier than air; will sink
Specific Gravity: 1.73 at 32°F (EPA, 1998) - Denser than water; will sink
Boiling Point: 38.4°F at 760 mmHg (EPA, 1998)
Molecular Weight: 94.95 (EPA, 1998)
Water Solubility: 2 % (NIOSH, 2024)
Ionization Energy/Potential: 10.54 eV (NIOSH, 2024)
IDLH: 250 ppm ; A potential occupational carcinogen. (NIOSH, 2024)

AEGLs (Acute Exposure Guideline Levels)

Final AEGLs for Methyl bromide (74-83-9)
Exposure Period AEGL-1 AEGL-2 AEGL-3
10 minutes NR 940 ppm 3300 ppm
30 minutes NR 380 ppm 1300 ppm
60 minutes NR 210 ppm 740 ppm
4 hours NR 67 ppm 230 ppm
8 hours NR 67 ppm 130 ppm
NR = Not recommended due to insufficient data
(NAC/NRC, 2024)

ERPGs (Emergency Response Planning Guidelines)

Chemical ERPG-1 ERPG-2 ERPG-3
Methyl Bromide (74-83-9) NA 100 ppm 300 ppm
NA = not appropriate.
(AIHA, 2022)

PACs (Protective Action Criteria)

Chemical PAC-1 PAC-2 PAC-3
Methyl bromide; (Bromomethane) (74-83-9) 19 ppm 210 ppm 740 ppm LEL = 100000 ppm
(DOE, 2024)

Regulatory Information

EPA Consolidated List of Lists

Regulatory Name CAS Number/
313 Category Code
EPCRA 302
EHS TPQ
EPCRA 304
EHS RQ
CERCLA RQ EPCRA 313
TRI
RCRA
Code
CAA 112(r)
RMP TQ
Bromomethane 74-83-9 1000 pounds 1000 pounds 1000 pounds 313 U029
Methyl bromide 74-83-9 1000 pounds 1000 pounds 1000 pounds X U029

(EPA List of Lists, 2024)

CISA Chemical Facility Anti-Terrorism Standards (CFATS)

No regulatory information available.

OSHA Process Safety Management (PSM) Standard List

Chemical Name CAS Number Threshold Quantity (TQ)
Methyl Bromide 74-83-9 2500 pounds

(OSHA, 2019)

Alternate Chemical Names