Which piece of legislation is primarily responsible for data protection in the European Union?

The General Data Protection Regulation (GDPR) is the primary piece of legislation responsible for data protection in the European Union. It was implemented to create a comprehensive framework for the protection of personal data and privacy rights for individuals within the EU. The GDPR enhances individuals' control over their personal data, ensuring that organizations are held accountable for the way they process personal information. It establishes stringent requirements for data processing, consent, data subject rights, and penalties for non-compliance.

The other pieces of legislation mentioned – the Data Protection Act (DPA), HIPAA, and the California Consumer Privacy Act (CCPA) – are significant in their respective contexts but do not govern data protection across the EU. The DPA refers to the UK's data protection framework prior to and following Brexit, HIPAA pertains specifically to health information in the United States, and CCPA focuses on privacy rights for California residents. Thus, while these laws play important roles in data protection and privacy, the GDPR stands out as the key legislation for data protection in the European Union.