Hamilton Construction Data Breach: SSNs & Names Exposed

On June 19, 2025, Hamilton Construction Co., a heavy civil contractor, experienced a significant cybersecurity event affecting current and former employees. Beginning on Nov. 12, 2025, the breach was disclosed to the Attorney General's offices in Washington, Montana and Oregon.

According to the notice, Hamilton became aware of suspicious activity on it's network and began an investigation. The data breach affected 610 Washington residents. When the preliminary review concluded on Oct. 7, 2025, Hamilton determined that an unauthorized party had gained access to the network and certain files on June 19, 2025.

The data exposed potentially includes personally identifiable information (PII) such as name, Social Security number, driver’s license or Washington ID card number, full date of birth, passport number, taxpayer identification number and financial or banking information.

In addition, some files contained protected health information (PHI), including health insurance policy or ID numbers and medical information. The exposure of both PII and PHI puts individuals at risk for identity theft and medical fraud.

Hamilton Construction Company's response

In response to the breach, Hamilton Construction Co. conducted an assessment, secured its systems, identified affected individuals, and notified relevant authorities. The company is offering 12 months of complimentary credit monitoring and identity restoration services through Epiq.

If you receive a data breach notice from Hamilton Construction Company you may want to:

• Sign up for the free credit monitoring and identity theft protection services, offered by the company.
• Monitor your credit reports and financial accounts for any unusual activity.
• Be alert for phishing emails or phone calls that may use your exposed information.
• Consider placing a fraud alert or credit freeze with major credit bureaus.

If you have additional questions, Hamilton has set up a dedicated call center for impacted individuals at 855-720-2945, Monday through Friday, between the hours of 9:00 a.m. and 9:00 p.m. ET.