Diazomethane

Generated on-site in research and industrial labs; usually used immediately in solution. It is rarely present in the general environment [1].

Breathing vapors during lab synthesis/use, leaks, or spills; direct contact with eyes/skin. The public is unlikely to be exposed except during a lab incident [1].

Strong lung, eye, and skin irritant; can cause delayed, life‑threatening fluid in the lungs (pulmonary edema). IARC classifies diazomethane as probably carcinogenic to humans (Group 2A) [1][2].

Chemists, analytical lab personnel, maintenance workers in labs, and emergency responders; people with asthma or lung disease may be more sensitive [1].

Use closed systems and certified fume hoods, keep quantities minimal, avoid storage, follow strict SOPs and training, wear appropriate PPE, and consider safer substitutes (e.g., trimethylsilyldiazomethane). In a community incident, follow public health and evacuation guidance [1].