The RFS regulations specify that foreign producers of ethanol for use in transportation fuel, heating oil or jet fuel for import to the US who do not add denaturant to their product, must register under RFS. See 80.1450(b) and 80.1401(definition of "foreign ethanol producer").
The regulations also specify that importers may not generate RINs for renewable fuel made with ethanol produced by such a foreign producer, unless the foreign producer is registered with EPA. See 80.1426(c)(4).