Oracle 11g: IMP hangs

Reference:  https://forums.oracle.com/forums/thread.jspa?threadID=689667

Check USED_UBLK and USED_UREC in V$TRANSACTION to see if an INSERT is really running (in which case these values would be increasing). 

select USED_UBLK , used_urec from v$transaction ;

monitor V$SESSION_WAIT for that import session to see what it is waiting on: