Protecting Firefighters from Adverse Substances Act of 2019 or the PFAS Act of 2019 This bill requires the Federal Emergency Management Agency (FEMA) to develop guidance for firefighters and other emergency response personnel on training, education programs, and best practices to protect them from exposure to perfluoroalkyl and polyfluoroalkyl substances, commonly referred to as PFASs, from firefighting foam and to limit or prevent the release of PFASs into the environment. These substances are man-made and may have adverse human health effects. A variety of products contain the compounds, such as nonstick cookware or weatherproof clothing. FEMA shall (1) develop and issue guidance on alternative foams, personal protective equipment, and other firefighting tools and equipment that do not contain PFASs; and (2) create an online public repository on tools and best practices to reduce, limit, and prevent the release of and exposure to PFASs.