AsianFin -- Chinese purchases of U.S. ethane, a key petrochemical feedstock, face fresh uncertainty after the U.S. Commerce Department instructed exporters to obtain licenses before shipping to China, according to trade sources and shipping data.

Washington has ordered a wide range of companies to halt shipments of goods—including ethane and butane—to China without prior approval, and has revoked previously granted licenses for some suppliers, Reuters reported on Wednesday.