Narrative:

Small transport X called ready for takeoff full length runway 1L, I told him to hold short 'landing traffic.' when the traffic, an small transport Z, crossed the landing threshold I told small transport X to taxi into position and hold. The small transport Z was cleared for stop and go, but never landed and flew low over the runway. Ground control called for crossing 1L at bravo intersection behind departing traffic. I said cross 1L at bravo. I then cleared small transport X for takeoff, the small transport Z was abeam intersection microphone which is the first intersection north of intersection bravo. I don't remember if I thought at the time ground meant the small transport Z or the small transport X holding full length reference the cross behind the departing traffic. I might have thought he meant the small transport X holding in position, but I really don't remember. I cleared the small transport X for takeoff as soon as I was sure the small transport Z was in a climb because it looked as if he was going to land twice, but never did. As soon as I cleared the small transport X I scanned the runway again and saw an small transport Y starting to cross the runway at bravo and said hold short to the small transport X, but thought I said hold your position. The small transport X (pilot) said he couldn't hold short he was on the runway, at the same time the small transport Y was already across and I cleared the small transport X again. It appeared the small transport X had only rolled about 500' at the time I cleared him the second time. The visibility was low to the south and I couldn't see the small transport X very well.

Google
 

Original NASA ASRS Text

Title: POOR INTRAFAC COORD AND LCL CTLR CLEARED SMT FOR TKOF AFTER APPROVING A RWY CROSSING FOR ANOTHER SMT. FIRST SMT ABORTED TKOF.

Narrative: SMT X CALLED READY FOR TKOF FULL LENGTH RWY 1L, I TOLD HIM TO HOLD SHORT 'LNDG TFC.' WHEN THE TFC, AN SMT Z, CROSSED THE LNDG THRESHOLD I TOLD SMT X TO TAXI INTO POS AND HOLD. THE SMT Z WAS CLRED FOR STOP AND GO, BUT NEVER LANDED AND FLEW LOW OVER THE RWY. GND CTL CALLED FOR XING 1L AT BRAVO INTXN BEHIND DEPARTING TFC. I SAID CROSS 1L AT BRAVO. I THEN CLRED SMT X FOR TKOF, THE SMT Z WAS ABEAM INTXN MIKE WHICH IS THE FIRST INTXN N OF INTXN BRAVO. I DON'T REMEMBER IF I THOUGHT AT THE TIME GND MEANT THE SMT Z OR THE SMT X HOLDING FULL LENGTH REF THE CROSS BEHIND THE DEPARTING TFC. I MIGHT HAVE THOUGHT HE MEANT THE SMT X HOLDING IN POS, BUT I REALLY DON'T REMEMBER. I CLRED THE SMT X FOR TKOF AS SOON AS I WAS SURE THE SMT Z WAS IN A CLB BECAUSE IT LOOKED AS IF HE WAS GOING TO LAND TWICE, BUT NEVER DID. AS SOON AS I CLRED THE SMT X I SCANNED THE RWY AGAIN AND SAW AN SMT Y STARTING TO CROSS THE RWY AT BRAVO AND SAID HOLD SHORT TO THE SMT X, BUT THOUGHT I SAID HOLD YOUR POS. THE SMT X (PLT) SAID HE COULDN'T HOLD SHORT HE WAS ON THE RWY, AT THE SAME TIME THE SMT Y WAS ALREADY ACROSS AND I CLRED THE SMT X AGAIN. IT APPEARED THE SMT X HAD ONLY ROLLED ABOUT 500' AT THE TIME I CLRED HIM THE SECOND TIME. THE VISIBILITY WAS LOW TO THE S AND I COULDN'T SEE THE SMT X VERY WELL.

Data retrieved from NASA's ASRS site as of August 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.