US and Mexico Establish Joint Enforcement Measures to Prevent Tariff Evasion on Steel and Aluminum

The United States and Mexico have implemented joint trade enforcement measures designed to prevent Chinese steel and aluminum from bypassing US tariffs, according to reports from the Associated Press, Wall Street Journal, and Reuters. The agreement, announced on July 5, 2026, represents a coordinated effort to close transshipment loopholes and protect the integrity of the North American market.

Under the newly established rules, steel imported from Mexico must meet a strict “melted and poured” standard to qualify for duty-free status under the United States-Mexico-Canada Agreement (USMCA). This requirement dictates that the steel must be entirely melted and poured within North America—specifically the United States, Mexico, or Canada. Any steel imports failing to meet this standard will face a 25% tariff when entering the United States.

Similarly, the agreement targets aluminum imports to prevent the circumvention of existing trade barriers. Under the joint enforcement measures, aluminum imports from Mexico must not contain primary metal smelted in China, Russia, Belarus, or Iran to avoid a 10% tariff. This measure aims to restrict the entry of subsidized or heavily tariffed metals into the US market through Mexican intermediaries.

Industry analysts note that these measures are likely to have significant implications for regional supply chains. By requiring strict documentation of the origin of raw materials, the agreement increases compliance obligations for manufacturers and exporters across North America. However, it also provides a level of protection for domestic metal producers within the USMCA bloc who have faced pressure from cheaper foreign imports.

According to the Associated Press, the joint enforcement strategy highlights the growing alignment between the US and Mexico on trade defense mechanisms. The Wall Street Journal reports that the “melted and poured” standard is a substantial shift that will require closer monitoring of supply chains, while Reuters notes that the rules are intended to address long-standing concerns regarding the transshipment of Chinese metals through third countries.

The implementation of these rules underscores the tightening of trade borders within North America. By establishing clear origin requirements for both steel and aluminum, the US and Mexico aim to ensure that the benefits of the USMCA are reserved for member nations rather than external producers. This coordinated action reflects a broader trend of regionalization in global trade, where nations increasingly rely on joint enforcement to protect domestic industries from external market distortions.