create table corrupt_lobs (corrupt_rowid rowid);

declare
error_1578 exception;
error_1555 exception;
error_22922 exception;
pragma exception_init(error_1578,-1578);
pragma exception_init(error_1555,-1555);
pragma exception_init(error_22922,-22922);
n number;
begin
for cursor_lob in (select rowid r, document from LOBDATA ) loop
begin
n:=dbms_lob.instr(cursor_lob.document,hextoraw('889911'));
exception
when error_1578 then
insert into corrupt_lobs values (cursor_lob.r);
commit;
when error_1555 then
insert into corrupt_lobs values (cursor_lob.r);
commit;
when error_22922 then
insert into corrupt_lobs values (cursor_lob.r);
commit;
end;
end loop;
end;
/

update LOBDATA set document = empty_blob()
where rowid in (select corrupt_lobs from corrupt_lobs);