Mexico Prepares NOM-251 Phase One Steel Certification

Steel News  |  2026-08-07 00:05:08   |   By

On Feb. 12, 2026, SE published the NOM-251-SE-2025, establishing mandatory certification and testing requirements for 26 steel product categories used in construction and infrastructure.

SEATTLE (Scrap Monster): The Ministry of Economy (SE) is about to implement the first stage of the Official Mexican Standard NOM-251-SE-2025. The entry into force of this norm will require local manufacturers and importers to comply with technical and commercial parameters to be allowed to be sold in the country. 

On Feb. 12, 2026, SE published the NOM-251-SE-2025, establishing mandatory certification and testing requirements for 26 steel product categories used in construction and infrastructure. The regulation, issued through the Directorate General of Standards, introduces a mandatory conformity assessment procedure designed to verify product dimensions, weight, chemical composition, mechanical properties, and labeling. 

The standard was formulated through a collaborative working group coordinated by SE’s National Advisory Committee on Standardization (CCONNSE). Key industry bodies, including the National Chamber of the Iron and Steel Industry (CANACERO), the National Association of Steel Transformers (ANTAAC), and the Mexican Association of Standardization and Certification (ANCE), participated alongside major steelmakers such as ArcelorMittal México, DEACERO, Gerdau Corsa, Ternium México, TenarisTamsa, TYASA, and Villacero.

While technical specifications previously existed under Mexican Standards (NMX), compliance verification was largely voluntary. Under NOM-251-SE-2025, compliance becomes legally binding, creating unified regulatory conditions for domestic steel producers and foreign suppliers entering the Mexican market.

Implementation will occur in two phases based on product classification. The first phase, effective Aug. 12, 2026, covers six structural product groups, including cold-rolled rebar, welded wire mesh, triangular steel trusses, steel armatures for castles and lintels, low-alloy rebar, and standard rebar. The second phase, covering the remaining 20 steel product families, such as structural tubing, steel plate, galvanized sheet, and steel cables, will take effect on Aug. 13, 2027.

The regulatory framework applies across the entire supply chain, affecting domestic steel manufacturers, importers, distributors, construction firms, and end consumers purchasing materials directly for self-construction.

Conformity assessment will be managed through accredited Product Certification Bodies and testing laboratories, with oversight and enforcement shared by SE, the Federal Consumer Protection Agency (PROFECO), and customs authorities. 

Mexico’s US Steel Market Share Drops to 9% Amid Expanding Section 232 Tariffs

Mexico’s position as a leading supplier of steel products to the United States weakened in 2025, with its share of total US imports declining despite integrated North American manufacturing supply chains. Data from the US International Trade Commission (USITC) shows total US imports of iron and steel articles under HTS Chapter 73 reached US$22.85 billion in 2025. Canada remained the largest foreign supplier at US$4.54 billion, representing 18% of total imports. Mexico supplied US$2.23 billion, representing 9% of the market, down from 11% in 2024. The dataset focuses on manufactured steel articles, including pipes, fasteners, structural components, and downstream products, as reported by MBN. 

The decline in market share coincided with modifications to the US Section 232 tariff regime. In April, the US government adjusted the tariff structure to apply duties to derivative products based on the value of their steel content. Further modifications in June lowered the required North American steel content threshold for preferential treatment from 95% to 85%. Concurrently, temporary tariff relief was established through 2027 for specific industrial equipment categories. According to the Congressional Research Service (CRS), US steel producers support these measures to encourage domestic investment, while downstream manufacturing consumers report higher input expenses across the automotive and construction sectors. Meanwhile, Canada maintains retaliatory tariffs on US$11.13 billion worth of US steel and aluminum goods.

Steel tariffs have emerged as a central issue for Mexico in the USMCA joint review. The Mexican government maintains that Section 232 tariffs increase costs for cross-border supply chains. To address the issue, Mexico proposed adopting a framework modeled on the US-UK trade agreement. The proposal conditions tariff-free market access on strict origin verification and melt-and-pour requirements to restrict third-country steel transshipment while allowing regional manufacturers preferential access. 

“The renegotiation window similarly provides a concrete opportunity to eliminate steel and aluminum tariffs. Because the United States does not run a trade deficit with Mexico in these specific commodities, the foundational justification for these protectionist measures does not apply,” commented Miriam Acuña, Chief Economist, GBM, in an interview with MBN.

Courtesy: www.mexicobusiness.news