As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAKEOFF AT IAD EN ROUTE FOR PHX RECEIVED DOOR WARNING INDICATION LT OVERWING EXIT, REJECTED TAKEOFF AT 79 KTS. MAINTENANCE FOUND THE COVER OVER THE LT OVERWING EMERGENCY EXIT LOOSE AND WEDGED IN DOOR, RESECURED COVER AND WARNING INDICATION EXTINGUISHED.