As the White House's new heavy tariffs on foreign steel and aluminum products become effective today, President Donald Trump is granting more exemptions to key allies to dodge a trade war with them. On Thursday, US Trade Representative Robert Lighthizer said the European Union, Argentina, Brazil, South Korea and Australia will not be subject to the trade penalties. Canada and Mexico had received exemptions earlier. So far, the tariffs don't apply to four top steel exporters, and four of the top seven aluminum exporters.