Yes—both diluted (ready-to-use) and concentrated antifreeze preparations classify under heading 3820, as the heading does not distinguish by concentration level. The key requirement is that the preparation is formulated to prevent freezing; the glycol content and inhibitor package do not affect the heading classification, though they are relevant to product specifications and labeling.

Yes. Airport-applied aircraft deicing fluids containing glycols are regulated under EPA stormwater and effluent guidelines because runoff can deplete oxygen in receiving waterways. Importers supplying airports should confirm that their products meet applicable environmental performance standards and that buyers have appropriate stormwater management plans in place.