Commerce Department will check corrosion-resistant products from five countries 

The U.S. Commerce Department announced on Wednesday that it would investigate whether steel products made in China and Taiwan and finished in other countries are evading U.S. tariffs. It is the first time the department started such an investigation on its own, rather than at the request of the private sector.

The Commerce Department will investigate corrosion-resistant products from Costa Rica, Guatemala, Malaysia, South Africa, and the United Arab Emirates. It will determine whether these products undergo only minor changes designed to mask their origins in China and Taiwan. If the investigation finds the products are illicitly avoiding tariffs, they will be subject to the additional levies.

The U.S. imposed anti-dumping and countervailing duties on corrosion-resistant steel from China and Taiwan last year. While shipments from the two fell, imports from the five countries now under investigation rose rapidly.

Until now, the Trump administration has initiated similar investigations 21 times in response to requests from companies. This time, however, the government started the investigation on its own based on import data.

The Trump administration has been on guard against goods trying to get around U.S. tariffs by traveling through third countries. As more goods start to flow through Vietnam, President Donald Trump has left open the possibility that he would impose additional trade levies against the country.