process living after logout

[Kenneth McDonald C60244 x3413]

We have recently discovered that when a person logs out from our Iris running
3.3.1 at random times a process will still show up when we xeq  % ps -ef

This process will look something like:

  b30607 12294     1  0 JAN 3    ttyd3     0:01 -csh

Could anyone tell me why this process stays behind?  Or is there a way of
making it die once you exit?  (besides kill -9 or killall)  

NOTE:  Notice that I said it occurs randomly.

Mail replies directly to me at:

           @aedc-vax.af.mil:c60244 at ccfiris.aedc

Thanks.