New tariffs now cover auto parts, machinery, plastics and chemicals. Importers face higher costs as total affected trade rises to $320 billion, up from $190 billion in 2024.
The United States has extended its 50% tariffs on steel and aluminium to 407 additional product categories. The measure took effect on 19 August, according to the Department of Commerce.
The list covers imports valued at $130 billion annually, based on 2024 customs data for the newly added codes. Combined with earlier tariffs, duties now apply to around $320 billion of imports, up from about US$190 billion previously.
Newly covered items include auto components, machinery, construction inputs, fire extinguishers, plastics and chemical derivatives. Products are identified only by 10-digit customs codes. For example, fire extinguishers are listed under code 8424.10.0000.
Tariffs on steel and aluminium were first imposed at 25%. In June 2025, the administration doubled rates to 50% for most countries. Monday’s expansion extends coverage beyond raw metals to downstream products.
The Department of Commerce said the step aims to prevent circumvention. Analysts note that the new list targets derivatives where steel or aluminium is an input, such as structural parts or packaging materials.
Michigan State University estimates that the new duties increase the value of affected imports by more than 68%. The figure is based on general customs value data for 2024.
Economists warn that higher duties could add cost-push inflation. The Producer Price Index for July already showed rising prices in steel-related categories. Importers are likely to face higher sourcing costs and compliance checks.
The Bureau of Industry and Security launched a product inclusion process in April. Companies filed requests in May, and the expanded list reflects those submissions.
Steel and aluminium remain central to U.S. trade policy. The White House has indicated that sector-specific tariffs will continue to be used to support domestic production and restrict targeted imports.
