Runner interference running to 1st Base

Question
We had a lefty slapper (16U) as she left front of box, and ran to 1st base headed for the safety bag but as I'm sure you know, she started in fair territory and angled her way towards the orange bag.  It was a drag type bunt and fielded by the catcher.  Her throw was off towards the foul side of my runner and it hit her right arm and then deflected towards the right field foul line.  My runner went to second base.  The opposing coach argued she was in the throwing lane and should be out for interference. The field ump said my runner's left foot was in fair territory when she was hit by the ball and therefore was out.  I have looked through the ASA rule book and can only find reference to runner interefence at first when runner uses white portion of base instead of safety bag and causes 1st baseman to be interfered with...nothing about having foot in fair territory and hit by a throw.  It was obviously not intentional and my runner was clearly headed towards the orange bag.  I am just trying to clarify the rule if it actually exists for future games.  Follow up question would be, is there a "running lane" or same ruling when no safety bag.  If white bag is in fair territory, I don't understand how runner is supposed to stay in foul territory and still run towards center of bag in that situation.  I appreciate any clarification if there is a rule I'm missing or misunderstand.

Answer
Hi Michael,

There is a running lane in FP and it is 30" from HP, in foul territory and 3" wide.  A b-runner is protected w/in that running lane unless they intentionally interfere w/ the throw.  

If she was in the lane with the left foot completely in fair territory she is considered out of the lane for that body part (touching any part of the line with any part of the foot is in the lane)BUT if hit in the right arm per your OP which is in the lane it is nothing.  If it hit her in the left leg and it interfered with the fielder taking the throw she would be out.  It is not the throw itself that causes interference but the interference with the ability of the fielder to take the throw.  So it must be a "quality" throw to start with, we don't play dodge softball.  If outside the lane did the runner's body interfere with the fielder's ability to take the throw? That is always the question. The interference has to do with not who's throwing it but who's receiving it.

There is no such thing as a "throwing lane"

I do not have an out in this situation.  Plus you need the league to chalk the lane and get safety bases.

Mark