What happens to the M211 flare when it comes into contact with oxygen?

When the M211 flare comes into contact with oxygen, it ignites due to the chemical composition and design intended to produce a bright light when activated. Flares are essentially pyrotechnic devices that rely on a chemical reaction, specifically combustion. In the presence of oxygen, the fuel in the flare burns vigorously, producing the intense light and heat characteristic of flares. This ignition is a critical aspect of their purpose, as they are often used for signaling and illumination in various scenarios. The flare's design is such that the combustion reaction is dependent on the availability of oxygen; hence, its ignition upon contact with oxygen is both expected and essential for its function.