Even after the Colombians and Mexicans started refining their own high grade heroin, there has always been some heroin coming from the Middle East and South East Asia. Chinese, Nigerians, Albanians, and others. But it's a relatively small part of the heroin trade.

The Chinese actually had about a decade or so - mid 1980s to mid 1990s - where they were on top of the heroin trade on the East Coast with their "China White." After the fall of the Pizza Connection and before the Colombians and later Mexicans took over.