Federal Firefighters Fairness Act of 2022 This bill provides federal workers' compensation to firefighters who contract certain illnesses as a result of their service. Specifically, the bill provides that heart disease, lung disease, and specified cancers of federal employees employed in fire protection activities for at least 5 years are presumed to be proximately caused by such employment if the employee is diagnosed with the disease within 10 years of employment. The Department of Labor must periodically review the bill's listed diseases and conditions and make appropriate additions. 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. Additionally, the Department of Interior and the Department of Agriculture must jointly study the long-term health effects experienced by federal wildland firefighters who are eligible for workers' compensation. The bill also requires Labor to revise regulations so as to allow at least 60 days (rather than at least 30 days) for a claimant to submit any additional evidence that is requested by the Office of Workers' Compensation Programs to support a federal workers' compensation claim.