In the company's HR department, internal emails may contain the following types of sensitive information about employees: 1. **Personal identification information**: such as name, address, telephone number, email address, ID number, etc. 2. **Compensation and benefits information**: including employee wages, bonuses, welfare plans, pension arrangements, etc. 3. **Performance evaluation**: results, feedback and evaluation reports on employee performance appraisals. 4. **Recruitment and hiring information**: including resumes, cover letters, interview feedback, etc. 5. **Contracts and agreements**: details of employment contracts, signed confidentiality agreements, etc. 6. **Health and medical information**: information related to employee health status and medical insurance plans. 7. **Training and development records**: including training courses attended, learning plans, personal development plans, etc. 8. **Disciplinary records**: records involving warnings, dismissals or other disciplinary actions. 9. **Leave and attendance records**: information on leave applications, sick leave records, attendance rates, etc. All of this information needs to be properly handled and protected to prevent unauthorized access and leakage.