A chemical that will self ignite when exposed to air is classified as what type of hazard?

A chemical that will self-ignite upon exposure to air is classified as a pyrophoric material. Pyrophoric substances have the ability to ignite spontaneously in air at or below 54 degrees Celsius (130 degrees Fahrenheit). This characteristic poses significant hazards during handling, storage, and transportation because they can ignite without an external ignition source, making them particularly dangerous in various environments.

In contrast, the other classifications do not accurately describe this behavior. Compressed gases refer to gases stored under pressure, which can explode or become hazardous when releasing gas rapidly but do not spontaneously ignite. Flammable materials require an external ignition source to catch fire, while oxidizers are substances that can cause or enhance the combustion of other materials but do not ignite themselves. Understanding the specific characteristics of pyrophoric materials is crucial for implementing appropriate safety protocols when working with such substances.