Answer:
Safe for who?
If the condom remains intact, with no breaks or leaks, it will be safe for both the man who is ejaculating and for the person who the anis belongs to.
Of course, if the condom breaks, then it becomes much less safe for the recipient; they are exposed to the man's semen and any germs (viruses or bacteria) that the man has. It is mess safe for the man ejaculating, too; he is exposed to the recipient's germs.