What type of chemicals are released during fire?

The type of chemicals released during a fire largely depends on what materials are burning. In our laboratory assessments, we frequently find a complex mixture of combustion by-products, especially when synthetic materials are involved.

Common substances include carbon monoxide, carbon dioxide, formaldehyde, benzene, acrolein, hydrochloric acid, dioxins, and a broad range of volatile organic compounds. When plastics burn, for example, they can release phthalates and brominated flame retardants—many of which are persistent and toxic.

Metals may also be released from treated woods, electronics, or construction materials, including lead, cadmium, and arsenic. These can settle as particulate residue or become airborne in smoke plumes.

It’s not uncommon for fire-damaged environments to contain dozens of different hazardous compounds, some of which interact with each other, forming new substances post-fire. That’s why comprehensive chemical analysis is vital—to identify and evaluate the full range of potential contaminants.