Which of the following would you NOT typically worry about in a chemical fire?

In a chemical fire, oxygen is a key component that supports combustion but is not a substance typically regarded as a specific concern or hazard during the event. Instead, the focus is usually on the various harmful chemical byproducts and gases that are produced during a fire involving chemicals.

Ozone, hydrogen cyanide, and chlorine are all potentially dangerous substances associated with certain chemical fires. For example, hydrogen cyanide can be released during the combustion of materials like plastics or certain textiles, leading to toxic exposure. Chlorine gas may be released from fires involving chlorinated compounds, and it poses serious respiratory hazards.

While oxygen does contribute to the combustion process, it is naturally present in the atmosphere and is not a toxic byproduct of chemical fires that poses a risk once fire has started. Therefore, in the context of a chemical fire, focusing on the toxic emissions and reactions is more critical than the presence of oxygen itself, making it the correct choice for something one would typically not worry about in this scenario.