Summary

Nucor, the largest steel producer company in the United States, has halted some productions due to its IT network being breached.

• “in an abundance of caution”, some operations were taken offline.
• A 3rd party (expert) is investigating.
• The federal authorities were notified about the incident.
• In the process of restarting shut down operations.

What

Some Nucro Steel operations.

Why

Operations were halted due to an IT security breach.

When

Today, Wednesday May 14th. Disclosed during its 8-K filing to the SEC. – source (PDF)

Where

• Some production processes in some facilities are offline.
• Did not name locations.

Sources

• https://www.theregister.com/2025/05/14/nucor_steel_attack/
• https://finance.yahoo.com/news/steelmaker-nucor-halts-production-cyber-105657047.html
• https://www.bleepingcomputer.com/news/security/steel-giant-nucor-corporation-facing-disruptions-after-cyberattack/
• https://therecord.media/cyber-incident-forces-nucor-steel-to-take-systems-offline