In which situation does a fire burn with the highest intensity?

A fire burns with the highest intensity in a high oxygen concentration environment. Oxygen is a critical component for combustion; it supports the chemical reactions that occur when fuel burns. When the concentration of oxygen is increased, the fire can consume fuel more efficiently and produce higher temperatures, resulting in a more intense blaze. This is due to the fact that an adequate supply of oxygen allows for a more complete combustion process, generating more heat and light.

In contrast, situations with low or no oxygen concentration hinder the combustion process. Low oxygen can lead to incomplete combustion, producing less heat and potentially resulting in smoldering fires rather than open flames. The absence of oxygen entirely would extinguish the fire since combustion cannot occur without it. Thus, a high concentration of oxygen facilitates the most vigorous and intense fire conditions.