Major airline had an office building at a major airport that was adjacent to their repair hangar. Office workers were complaining about having breathing problems while at work but were perfectly fine when they went home. It was determined that the complaints were real and that the workers were not allergic to work. Once this was established, a testing program was initiated. Pesticides were suspected but it was later found to be a cyclic siloxane compound that is used as a water repellant on the aircraft. EMSL was able to do identify the compound by GC/MS.