The deepest scuba dive made to date is somewhat in excess of 1000 ft.  It is a moving target.  As soon as someone sets the record someone else will break it.

There is no safe depth limit for scuba diving.  There is only an increasing level of risk.  Only a handful of divers have been past 800 ft.  Of those who have gone that deep, about half are dead.  Trying to break deep diving records is much like playing Russian Roulette.