On June 19, 2025, Hamilton Construction Co. suffered a cybersecurity breach exposing sensitive data of 610 Washington residents, including current and former employees. The unauthorized access compromised personally identifiable information (PII) such as Social Security numbers, driver’s license/ID details, full dates of birth, passport numbers, taxpayer IDs, and financial/banking data as well as protected health information (PHI), including health insurance policy numbers and medical records.The breach, disclosed to the Washington Attorney General’s office on November 12, 2025, followed a months-long investigation confirming the incident originated from suspicious network activity. The exposure of PII and PHI heightens risks of identity theft, financial fraud, and medical fraud for affected individuals. In response, Hamilton secured its systems, notified impacted parties, and offered 12 months of free credit monitoring and identity restoration services via Epiq. A dedicated call center was also established to assist victims.The breach underscores severe vulnerabilities in employee data protection, with long-term reputational and financial repercussions for the company and affected individuals.
Source: https://www.claimdepot.com/data-breach/hamilton-construction-company-2025
TPRM report: https://www.rankiteo.com/company/hamilton-construction-co.
"id": "ham2994229111825",
"linkid": "hamilton-construction-co.",
"type": "Breach",
"date": "6/2025",
"severity": "85",
"impact": "3",
"explanation": "Attack with significant impact with internal employee data leaks"{'affected_entities': [{'customers_affected': '610 (Washington residents)',
'industry': 'Heavy Civil Construction',
'location': 'Washington, USA',
'name': 'Hamilton Construction Co.',
'type': 'Private Company'}],
'customer_advisories': ['Dedicated call center for impacted individuals '
'(855-720-2945, Mon–Fri 9:00 AM–9:00 PM ET)',
'Public guidance on mitigating identity theft and '
'fraud risks'],
'data_breach': {'data_exfiltration': 'Likely (files accessed by unauthorized '
'party)',
'number_of_records_exposed': '610',
'personally_identifiable_information': True,
'sensitivity_of_data': 'High (PII and PHI)',
'type_of_data_compromised': ['Name',
'Social Security number',
'Driver’s license or Washington '
'ID card number',
'Full date of birth',
'Passport number',
'Taxpayer identification number',
'Financial or banking '
'information',
'Health insurance policy or ID '
'numbers',
'Medical information']},
'date_detected': '2025-06-19',
'date_publicly_disclosed': '2025-11-12',
'description': 'On June 19, 2025, Hamilton Construction Co., a heavy civil '
'contractor, experienced a significant cybersecurity breach '
'affecting current and former employees. An unauthorized party '
'gained access to the network and certain files, exposing '
'personally identifiable information (PII) and protected '
'health information (PHI) of 610 Washington residents. The '
"breach was disclosed to the Washington Attorney General's "
'office on Nov. 12, 2025. The company is offering 12 months of '
'complimentary credit monitoring and identity restoration '
'services through Epiq.',
'impact': {'brand_reputation_impact': 'Potential risk due to exposure of '
'sensitive employee data',
'data_compromised': ['Personally Identifiable Information (PII)',
'Protected Health Information (PHI)'],
'identity_theft_risk': 'High (due to exposure of SSN, driver’s '
'license, financial info, etc.)',
'payment_information_risk': 'High (financial/banking information '
'exposed)'},
'initial_access_broker': {'high_value_targets': ['Employee PII',
'Employee PHI']},
'investigation_status': 'Preliminary review concluded on 2025-10-07; '
'investigation likely ongoing',
'post_incident_analysis': {'corrective_actions': ['Systems secured (details '
'unspecified)',
'Credit monitoring services '
'provided to affected '
'individuals']},
'recommendations': ['Sign up for free credit monitoring and identity theft '
'protection services offered by Hamilton Construction Co.',
'Monitor credit reports and financial accounts for '
'unusual activity',
'Be alert for phishing emails or calls exploiting exposed '
'information',
'Consider placing a fraud alert or credit freeze with '
'major credit bureaus'],
'references': [{'source': 'Washington Attorney General’s Office (Data Breach '
'Notice)'}],
'regulatory_compliance': {'regulatory_notifications': ['Washington Attorney '
'General’s office '
'(disclosed on '
'2025-11-12)']},
'response': {'communication_strategy': ['Notice to Washington Attorney '
'General’s office',
'Data breach notices to affected '
'individuals',
'Dedicated call center for inquiries',
'Public advisory with recommended '
'actions (credit monitoring signup, '
'fraud alerts, etc.)'],
'containment_measures': 'Systems secured (details unspecified)',
'incident_response_plan_activated': True,
'recovery_measures': ['Assessment conducted',
'Affected individuals identified and '
'notified',
'Dedicated call center established '
'(855-720-2945)'],
'third_party_assistance': {'credit_monitoring_provider': 'Epiq',
'services_offered': ['12 months of '
'complimentary '
'credit '
'monitoring',
'Identity '
'restoration '
'services']}},
'threat_actor': 'Unauthorized party',
'title': 'Hamilton Construction Co. Data Breach (2025)',
'type': 'Data Breach'}