begin
OWA_UTIL.mime_header ('text/csv', FALSE);
htp.p('Content-Disposition:attachment;filename="report.csv"');
OWA_UTIL.http_header_close;
  htp.p('№ договора;Фамилия;Имя;Отчество'); 
  for x in (select ...
              from ...
             where ...) loop
   
      htp.p(
            x.agreement_nm || ';' ||
            x.last_name || ';' ||
            x.fst_name || ';' ||
            x.mid_name);
  end loop;
apex_application.g_unrecoverable_error:=true;
exception when others then 
null;
end;

declare
  v_crep_text clob;
  v_brep_text blob;
  dest_offset integer := 1;
  src_offset  integer := 1; 
  v_warn      integer;
  l_context   integer := 0;
  err_msg varchar2(4000);
begin
  v_crep_text:= 'заголовок csv отчета' || chr(10); 

  for x in (select ...
              from ...
             where ...) loop
   
      v_crep_text := v_crep_text || ... || chr(10);

  end loop;

  dbms_lob.createtemporary(v_brep_text, TRUE);
  dbms_lob.open(v_brep_text, dbms_lob.lob_readwrite);
   
  dbms_lob.converttoblob(v_brep_text, v_crep_text, DBMS_LOB.LOBMAXSIZE, dest_offset, src_offset, l_context, l_context, v_warn);

  OWA_UTIL.mime_header ('text/html', FALSE, 'cp1251');
  htp.p('Content-Disposition:attachment;filename="report.csv"');
  htp.p('Content-length: ' || dbms_lob.getlength(v_brep_text)); 
  OWA_UTIL.http_header_close;

  wpg_docload.download_file(v_brep_text); 
  
  apex_application.g_unrecoverable_error:=true;
exception 
  when others then 
    null;
end;