Narrative:

Ground control gave permission to taxi. Upon taxiing from FBO (bfi) inadvertently started to enter runway. Stopped when advised by controller and taxied back to hold short line. Had crossed hold short but had not actually proceeded onto runway itself. The taxi area crosses what appears to be FBO parking and what appears to be taxiway is actually the runway. Pilot was observant as should be, controller was paying attention and may have prevented a very serious accident. How about painting 'stop' at runway-taxiway intxns? (Not trying to excuse my error!) pilot had been to bfi only once previously.

Google
 

Original NASA ASRS Text

Title: AN SMA PLT TAXIED ONTO THE RWY INADVERTENTLY. THE GND CTLR HAD TO POINT THIS OUT TO THE PLT.

Narrative: GND CTL GAVE PERMISSION TO TAXI. UPON TAXIING FROM FBO (BFI) INADVERTENTLY STARTED TO ENTER RWY. STOPPED WHEN ADVISED BY CTLR AND TAXIED BACK TO HOLD SHORT LINE. HAD CROSSED HOLD SHORT BUT HAD NOT ACTUALLY PROCEEDED ONTO RWY ITSELF. THE TAXI AREA CROSSES WHAT APPEARS TO BE FBO PARKING AND WHAT APPEARS TO BE TAXIWAY IS ACTUALLY THE RWY. PLT WAS OBSERVANT AS SHOULD BE, CTLR WAS PAYING ATTN AND MAY HAVE PREVENTED A VERY SERIOUS ACCIDENT. HOW ABOUT PAINTING 'STOP' AT RWY-TAXIWAY INTXNS? (NOT TRYING TO EXCUSE MY ERROR!) PLT HAD BEEN TO BFI ONLY ONCE PREVIOUSLY.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.