 In what appears to be an effort to prevent China from using Mexico to do an end run around steel and aluminum import tariffs, the Biden administration says it will impose new tariffs on those items that are not produced in Mexico but are being shipped from there. Tariffs would be levied as part of an agreement with Mexico to take action on imports that could threaten U.S. national security. It would be a 25 percent tariff on steel and a 10 percent tariff on aluminum not poured in the country but routed through there.