Officials from Carnival Corporation & plc announced on Thursday that a data breach in March might have exposed personal information about customers and employees.

According to The Associated Press , the company revealed that hackers might have gained access to Social Security numbers, passport numbers, dates of birth, addresses and health information from crew members and passengers with Carnival Cruise Line, Holland America Line and Princess Cruises.

The data breach was detected on March 19, with Carnival officials shutting down access and hiring a cybersecurity company to investigate immediately. The company has been working to improve the security of its information systems since it was hit twice last year by ransomware attacks.

While Carnival declined to say how many people were impacted by the breach, company spokesman Roger Frizzell said all of the passengers and employees affected were notified and a call center was set up to answer questions.

Last month, Carnival Corporation announced it received the U.S. Centers for Disease Control & Prevention’s (CDC) approval of its Phase 2A Port Agreements for PortMiami, Port of Galveston and Port Canaveral.

Last week, Princess Cruises will introduce a new MedallionClass feature that allows guests to call a crew member wherever they are on the ship, called CrewCall.