BWI Marshall Airport –  An unknown substance found on board a Southwest aircraft was determined to be fibers from a tissue box

A Southwest flight #239 originating from San Antonio, Tx, was met by the Fire and Rescue Department and other appropriate authorities who safely deplaned the flight and tested the substance found in the toilet area of the airplane.

”Fire and Rescue Department @BWIFire and other authorities investigated unknown substance on board an aircraft that has arrived at airport. Testing indicated there was no hazard. The scene was secured.

The aircraft has been cleared to resume services.