A factory that specializes in the refinement of transition metals such as titanium was on fire. The firefighters were advised not to douse the fire with water. Why?

Titanium is known for its strength, light weight, and high resistance to corrosion, making it valuable in aerospace, medical, and sporting goods industries. Despite its reactivity with oxygen at high temperatures forming a passive oxide layer, titanium's reaction with water can be hazardous. At room temperature, titanium is relatively inert due to this oxide layer, but at higher temperatures, as seen in fires, it can react vigorously with water.
This reaction produces titanium dioxide, a white pigment commonly used in paints and cosmetics, along with hydrogen gas. The titanum-water reactivity underlines the importance of understanding chemical properties when dealing with fire incidents involving transition metals like titanium.

Hydrogen gas has the notorious distinction of being highly flammable. It can ignite in air at a wide range of concentrations, from about 4% to 75% by volume, and its flame is almost invisible to the naked eye in daylight. The energy released during its combustion process is intense, which is why hydrogen is both a promising clean fuel and a hazard in fire situations.
When titanium reacts with water at high temperatures, it produces hydrogen gas as a by-product, thus posing a significant risk of exacerbating fires or causing explosions. Due to these properties, controlling the source of hydrogen gas during fires is crucial for chemical safety.

Not all metals react with water, but those who do, such as sodium or potassium, can do so explosively, especially in their metallic form. Transition metals like titanium usually react less violently, but in high-temperature scenarios, such as a fire, even these less reactive metals can engage in hazardous reactions.
In these situations, metal reacts with water to release hydrogen gas and a corresponding metal hydroxide or oxide. This is a redox reaction wherein the metal is oxidized and the water, or more specifically the hydrogen in the water, is reduced. Hence, introducing water to a metal fire can inadvertently supply a flammable gas to the already dangerous situation.

The paramount goal in any fire is to ensure the safety of individuals and minimize damage to property. Chemical safety in fires involves understanding the nature of the materials involved and how they react under conditions of high heat. In the context of titanium, introducing water can instigate a reaction producing flammable hydrogen, escalating the fire threat.
The training of firefighters includes knowledge about chemical reactions to prevent well-intentioned actions from becoming life-threatening. It's also important to consider evacuation, containment, and appropriate fire suppression agents like dry powder for certain metal fires. Understanding the properties of materials and the risks associated with them is essential for ensuring chemical safety in fires.