Steel manufacturer Nucor halts production after cybersecurity incident

Nucor, the biggest steel manufacturer in North America, has shut down some of its operations due to a “cybersecurity incident.”

Nucor Corporation is a manufacturer that produces steel and related products. In 2024, the company produced and sold approximately 18.5 million tons of steel and recycled 18 million tons of scrap.

That same year, Nucor had a revenue of over $30.7 billion and a gross profit of $4.1 billion. According to the latest numbers, over 32,700 people are employed by the Charlotte, North Carolina-based steel company.

In an 8-K Form addressed to the Securities and Exchange Commission (SEC), Nucor states that it has recently identified a “cybersecurity incident” involving an unauthorized third-party that accessed certain IT systems.

“Upon detecting the incident, the company began promptly taking steps to contain and respond to the incident, including activating its incident response plan, proactively taking potentially affected systems offline and implementing other containment, remediation, or recovery measures,” the filing reads.

At the moment, Nucor has temporarily shut down certain product operations at various locations. Although the company is currently investigating the incident with external leading cybersecurity experts, it’s also in the process of restarting the affected operations.

Nucor has notified federal law enforcement authorities.

“As the investigation of the incident is ongoing, the company will continue to monitor the timing and materiality of the incident,” Nucor concludes in its 8-K Filing.

As of writing, Nucor refuses to share more details about the incident, meaning it’s unclear who’s responsible, if any personal or corporate information has been stolen, and how the attackers managed to get into the company’s IT systems.

No ransomware operation has so far claimed responsibility.