Pierce County Library Data Breach Impacts 340,000

Pierce County Library System (PCLS) has notified over 340,000 people that their personal information was compromised in a data breach, with the incident spanning 15–21 April 2025 as threat actors accessed the network and stole data.

The library says the breach affects patrons and current and former employees and their family members, and that for patrons the compromised information includes names and dates of birth, while employees and relatives could have names, dates of birth, Social Security numbers, driver’s licence numbers, passport numbers, financial information, credit card details, and health insurance and medical information.

The Maine Attorney General’s Office reports that the incident impacts 340,101 individuals and that written notifications are being sent. Affected individuals are offered 12 months of free credit monitoring and identity protection services. PCLS has not shared details on the threat actors responsible, and SecurityWeek has not seen any known ransomware group claiming responsibility for the data breach. According to SecurityWeek, the library’s incident notice is referenced on its site.