A process chamber is configured to contain a work piece in a controlled atmosphere and to perform a process that emits pyrophoric particulates. A closed recirculating loop connected with the process chamber recirculates gas defining the controlled atmosphere through the process chamber. A filter in the closed recirculating loop captures the generated pyrophoric particulates in the recirculating gas. A valve set has a work configuration defining the closed recirculating loop including the connection of the process chamber with the filter, and a filter regeneration configuration in which the filter is blocked off from the process chamber and is connected with an exhaust. A work piece is loaded into the process chamber. With the valve set in the work configuration, the process is performed on the loaded work piece. Thereafter, regeneration gas containing oxygen is delivered to the filter with the valve set in the regeneration configuration.