How many classes are unstable (reactive) materials divided into based on hazard level?

Unstable (reactive) materials are categorized into four classes based on their hazard level and the type of reaction they can undergo. This classification system helps ensure that workers in laboratories and industries understand the specific risks associated with different materials and can take appropriate precautions when handling them.

The four classes generally include:

1. Class 1: Materials that are normally stable but may become unstable under certain conditions, such as exposure to heat or shock.

2. Class 2: Materials that are unstable at room temperature and can undergo rapid decomposition, even without an external ignition source.

3. Class 3: Materials that may polymerize violently, producing heat and gas, leading to explosive situations.

4. Class 4: Materials that can undergo explosive reactions without the need for an external energy source, posing significant dangers in a laboratory setting.

Understanding this classification system is crucial for the safe handling and storage of reactive materials in laboratories, ensuring that proper safety protocols are in place to mitigate any potential hazards.