Federal Firefighters Fairness Act of 2019 This bill provides federal worker's compensation to firefighters who contract certain illnesses as a result of their service. Specifically, the bill provides that (1) heart disease, lung disease, and specified cancers of federal employees employed in fire protection activities for at least 5 years is presumed to be proximately caused by such employment if the employee is diagnosed with the disease within 10 years of their employment in fire protection activities; and (2) the disability or death of the employee due to such disease is presumed to result from personal injury sustained in the performance of duty. These presumptions also apply to fire protection employees who contract any uncommon infectious disease, such as tuberculosis, hepatitis A, B, or C, or the human immunodeficiency virus (HIV). An employee in fire protection activities is a firefighter, paramedic, emergency medical technician, rescue worker, ambulance personnel, or hazardous material worker, who (1) is trained in fire suppression; (2) has the legal authority and responsibility to engage in fire suppression; (3) is engaged in the prevention, control, and extinguishment of fires or response to emergency situations where life, property, or the environment is at risk; and (4) performs such activities as a primary responsibility. The National Institute of Occupational Safety and Health in the Centers for Disease Control and Prevention must examine the implementation of this bill and appropriate scientific and medical data related to the health risks of firefighting.