system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do explosives such as C4 smell of Almonds?
gpt
When they manufacture C4 they add a chemical (2,3-dinitro-2,3-dimethylbutane, DMNB) to the explosive. This is done to intentionally make the explosive easy to identify by dogs. This particular chemical can be detected by dogs in incredibly minute quantities.

It's to prevent people sneaking it onto planes or other secured places.