May explosively decompose on shock, friction, or concussion. Contact with alkali metals and calcium sulfate causes explosions. The substance is very corrosive to the eyes, the skin and the respiratory tract. The liquid may cause frostbite. Exposure above the OEL may result in death.
Medical observation is indicated.
Repeated or prolonged inhalation exposure may cause asthma. This substance is possibly carcinogenic to humans. Because of its toxicity and its explosive nature, diazomethane is freshly prepared in situ and used in solution of ether or dioxane, the symptoms of lung oedema 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, the relation between odour and the occupational exposure limit cannot be indicated, the recommendations on this Card also apply to concentrated solutions of diazomethane.