Chemical Datasheet


4.1 - Flammable solid

Chemical Identifiers

CAS Number UN/NA Number DOT Hazard Label USCG CHRIS Code
  • 7439-95-4
  • 1869
  • Flammable Solid
  • MGX
NIOSH Pocket Guide International Chem Safety Card
NFPA 704
Diamond Hazard Value Description
0 1
Blue Health 0 No hazard beyond that of ordinary combustible material.
Red Flammability 1 Must be preheated before ignition can occur.
Yellow Instability 1 Normally stable but can become unstable at elevated temperatures and pressures.
White Special
(NFPA, 2010)
General Description
A light silvery metal. The more finely divided material reacts with water to liberate hydrogen, a flammable gas, though this reaction is not as vigorous as that of sodium or lithium with water. In finely divided forms is easily ignited. Burns with an intense white flame. Can be wax coated to render magnesium as nonreactive.


Reactivity Alerts
Air & Water Reactions
Magnesium ribbon and fine magnesium shavings can be ignited at air temperatures of about 950°F and very finely divided powder has been ignited at air temperatures below 900°F. [Magnesium Standard 1967 p. 4]. May react slowly with water to liberate hydrogen, a flammable gas.
Fire Hazard
Behavior in Fire: Forms dense white smoke. Flame is very bright. (USCG, 1999)
Health Hazard
Dust irritates eyes in same way as any foreign material. Penetration of skin by fragments of metal is likely to produce local irritation, blisters, and ulcers which may become infected. (USCG, 1999)
Reactivity Profile
MAGNESIUM slowly oxidizes in moist air. Reacts very slowly with water at ordinary temperatures, less slowly at 100°C. Reacts with aqueous solutions of dilute acids with liberation of hydrogen [Merck 11th ed. 1989]. In the presence of carbon, the combination of chlorine trifluoride with aluminum, copper, lead, magnesium, silver, tin, or zinc results in a violent reaction [Mellor 2, Supp. 1. 1956]. A mixture of powdered magnesium with trichloroethylene or with carbon tetrachloride will flash or spark under heavy impact [ASESB Pot. Incid, 39. 1968]. Stannic oxide, heated with magnesium explodes [Mellor 7:401. 1946-47]. When carbon dioxide gas is passed over a mixture of powdered magnesium and sodium peroxide, the mixture exploded [Mellor 2:490. 1946-47]. Powdered magnesium plus potassium (or sodium) perchlorate is a friction-sensitive mixture [Safety Eng. Reports. 1947]. An explosion occurred during heating of a mixture of potassium chlorate and magnesium [Chem. Eng. News 14:451. 1936]. Powdered magnesium can decompose performic acid violently [Berichte 48:1139. 1915]. A mixture of finely divided magnesium and nitric acid is explosive [Pieters 1957. p. 28]. Magnesium exposed to moist fluorine or chlorine is spontaneously flammable [Mellor 4:267. 1946-47].
Belongs to the Following Reactive Group(s)
Potentially Incompatible Absorbents

No information available.

Response Recommendations

Isolation and Evacuation
Excerpt from ERG Guide 138 [Substances - Water-Reactive (Emitting Flammable Gases)]:

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)
Fire Extinguishing Agents Not to Be Used: Water, foam, halogenated agents, carbon dioxide.

Fire Extinguishing Agents: Inert dry powders (e.g., graphite, limestone, salt) (USCG, 1999)
Non-Fire Response
Excerpt from ERG Guide 138 [Substances - Water-Reactive (Emitting Flammable Gases)]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames in immediate area). Do not touch or walk through spilled material. Stop leak if you can do it without risk. Use water spray to reduce vapors or divert vapor cloud drift. Avoid allowing water runoff to contact spilled material. DO NOT GET WATER on spilled substance or inside containers.

SMALL SPILL: Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain. Dike for later disposal; do not apply water unless directed to do so.

POWDER SPILL: Cover powder spill with plastic sheet or tarp to minimize spreading and keep powder dry. DO NOT CLEAN-UP OR DISPOSE OF, EXCEPT UNDER SUPERVISION OF A SPECIALIST. (ERG, 2016)
Protective Clothing
Eye protection (USCG, 1999)
DuPont Tychem® Suit Fabrics
No information available.
First Aid
EYES: flush with water to remove dust.

SKIN: treat as any puncture. (USCG, 1999)

Physical Properties

Chemical Formula:
  • Mg
Flash Point: data unavailable
Lower Explosive Limit (LEL): data unavailable
Upper Explosive Limit (UEL): data unavailable
Autoignition Temperature: 883 ° F (USCG, 1999)
Melting Point: 1202 ° F (USCG, 1999)
Vapor Pressure: data unavailable
Vapor Density (Relative to Air): data unavailable
Specific Gravity: 1.74 at 68 ° F (USCG, 1999)
Boiling Point: 2012 ° F at 760 mm Hg (USCG, 1999)
Molecular Weight: 24.3 (USCG, 1999)
Water Solubility: data unavailable
Ionization Potential: data unavailable
IDLH: data unavailable

AEGLs (Acute Exposure Guideline Levels)

No AEGL information available.

ERPGs (Emergency Response Planning Guidelines)

No ERPG information available.

PACs (Protective Action Criteria)

Chemical PAC-1 PAC-2 PAC-3
Magnesium (7439-95-4) 18 mg/m3 200 mg/m3 1200 mg/m3
(DOE, 2016)

Regulatory Information

EPA Consolidated List of Lists

No regulatory information available.

DHS Chemical Facility Anti-Terrorism Standards (CFATS)

Chemical of Interest CAS Number Min Conc STQ Security
Min Conc STQ Security
Min Conc STQ Security
Magnesium (powder) 7439-95-4 ACG 100 pounds EXP/IEDP

(DHS, 2007)

OSHA Process Safety Management (PSM) Standard List

No regulatory information available.

Alternate Chemical Names