Under the UN Labeling System, how is a substance that readily yields oxygen to support combustion labeled?

• A. 3
• B. 4
• C. 5
• D. 6

Answer: (C)

A substance that readily yields oxygen to support combustion is labeled with the number 5 under the UN Labeling System. This classification specifically designates oxidizers. Oxidizers are materials that can enhance the combustion of other substances by supplying the necessary oxygen, which can facilitate and accelerate fires.

Recognizing oxidizers is crucial for safety as they are often involved in incidents where fires can become uncontrollable. Their labeling is part of the effort to ensure first responders and handlers of these materials are aware of the potential risks associated with their use and storage. The use of the number 5 indicates not just the hazard but also provides guidance on appropriate handling procedures to mitigate risks associated with these substances. This is vital to maintain safety in environments where such materials are present.