3604 - Fireworks, signaling flares, rain rockets, fog signals and other pyrotechnic articles:

This HTS category, 3604, encompasses a range of pyrotechnic articles designed for specific signaling or recreational purposes. The core characteristic of these items is their ability to produce visual or audible effects through controlled combustion. This includes, but is not limited to, fireworks designed for entertainment, signaling flares used for emergencies or navigation, rain rockets, and fog signals intended for maritime or railway use. The common thread is their pyrotechnic nature, meaning they contain combustible substances that, when ignited, generate heat, light, gas, or smoke.

Distinguishing this category from its broader sibling categories within Section VI, such as those for explosives (Chapter 36) or other chemical products, is crucial. While other categories may also involve chemical reactions or combustion, HTS 3604 specifically targets articles whose primary function is pyrotechnic display or signaling. For instance, materials that are purely explosive components without a defined pyrotechnic application would fall under different headings within Chapter 36.

Within HTS 3604, two main subcategories exist to further refine classification. The first, 3604.10, specifically addresses "Fireworks," which are designed for amusement and produce visual effects like sparks, colored lights, and noise. The second, 3604.90.00.00, acts as a residual category for "Other" pyrotechnic articles not elsewhere specified, encompassing items like signaling flares and fog signals whose primary function is communication or safety, rather than entertainment.