A Texas seaport handling booming exports of U.S. crude oil has invoked a 12-year-old criminal case against the commodities trading house Trafigura as it seeks to slow its efforts to build an alternative site to load supertankers.

The Port of Corpus Christi has emerged as a high-volume conduit for oil exports since the U.S. legalized them in late 2015. The shipments have generated millions of dollars in revenue for the public agency that operates the port, according to Morningstar.

Trafigura is a big shipper at the port as one of the top exporters of U.S. crude, moving barrels through the Buckeye Partners LP (NYSE: BPL) terminal on the Corpus Christi docks.