Diazomethane is a highly toxic, flammable, corrosive, and reactive gas. Because of its acute toxicity and unstable nature, diazomethane is freshly prepared in situ and used in solution of ether or dioxane. Diborane is spontaneously explosive above 100C, in contact with rough surfaces (i.e. ground glass), intense light, or if subjected to shock, friction or concussion. The odor threshold of the gas has not been established to be below the permissible exposure limit. Diazomethane is a suspected human carcinogen.

Emergency Procedures

Skin Contact: Skin contact may cause painful burns and irritation due to its corrosive nature. Frostbite may occur from contact with the liquid. Flush affected areas immediately with copious amounts of water for at least 15 minutes. Seek medical attention immediately.

Eye Contact: Corrosive to eye tissues, exposure indicated by redness and pain. Immediately flush with water for at least 15 minutes. Seek immediate medical attention.

Inhalation: Inhalation results in irritation of the respiratory tract and may cause headache, labored breathing, shortness of breath, sore throat, vomiting, malaise. Symptoms may be delayed. Overexposure may result in damage to the central nervous system, kidneys and liver. Death can result from pulmonary edema (fluid in the lungs) and/or lack of oxygen. The symptoms of lung edema and/or asthma often do not become manifest until a few hours have passed and they are aggravated by physical effort. Rest and medical observation are therefore essential. PROMPT MEDICAL ATTENTION IS NECESSARY IN ALL CASES OF OVEREXPOSURE. Conscious persons should be assisted to an area with fresh, uncontaminated air.

Ingestion: Not a likely route of exposure. Consult a poison control center or physician.


The gas is heavier than air and may travel along the ground; distant ignition possible. Earth-ground and bond all lines and equipment associated with the system. All electrical equipment should be non-sparking or explosion proof. Ensure that carbon dioxide fire extinguishers are available. Small quantities should be allowed to burn themselves out if safe to do so.

May explosively decompose on shock, friction, or concussion. May explode on heating at 100C, or on contact with rough surfaces or if impurities or solids are present in the undiluted liquid or in the concentrated solutions, or under high intensity lighting. Ground glass joints and scratches in glassware can cause diazomethane to explode. Contact with alkali metals and calcium sulfate causes explosions. Use of a blast shield is highly recommended while using this material.


Storage of this material is strongly discouraged due to its unstable nature. Commercially available solutions of trimethylsilyldiazomethane is recommended as a substitute for methylation reactions in lieu of diazomethane. If no substitute is available, prepare diazomethane in situ for immediate use. Flame polished joints (i.e. Clear Seal) are recommended for the glassware used for this material.


Small amounts of excess diazomethane can be destroyed by carefully adding acetic acid dropwise to a dilute solution of the diazomethane in an inert solvent such as ether at 0C. The neutralized solution, excess diazomethane solutions, and waste material containing this substance should managed as hazardous waste.

Section 10 Chemical List