Cyberattack Forces Nucor to Halt Operations at Multiple Facilities

Nucor Corporation, the largest steel producer in North America, halted operations at various facilities after detecting a cybersecurity incident involving unauthorized third-party access to its information technology systems. The breach, identified on May 13, 2025, prompted the Charlotte, North Carolina-based company to take several systems offline and activate its incident response protocols. In an SEC filing, Nucor disclosed it is working with federal law enforcement and external cybersecurity experts to investigate the breach and implement recovery measures.

The company is in the process of restarting affected operations as the investigation continues. Nucor has not disclosed which specific facilities were impacted by the shutdown. The incident highlights persistent cyber vulnerabilities in the manufacturing sector, which has faced the highest volume of cyberattacks for four consecutive years, according to IBM’s X-Force 2025 threat intelligence report. The disruption arrives during a financially pivotal time for Nucor, which reported $7.83 billion in first-quarter net sales amid broader industry challenges.