Presumptive Benefits for War Fighters Exposed to Burn Pits and Other Toxins Act of 2020 This bill establishes a presumption of service-connection for specified diseases associated with exposure to open burn pits (an area used for burning solid waste in open air without equipment) and other toxins by veterans who meet certain criteria. Under a presumption of service-connection, specific conditions diagnosed in certain veterans are presumed to have been caused by the circumstances of their military service. Health care benefits and disability compensation may then be awarded. The bill also makes disability or death from certain diseases due to service in support of a military operation for at least 15 days in a specified location compensable as a work injury.