Former pupils of teacher John Owen say they hope the inquiry into his sex abuse will help protect potential future victims.
Victims say nobody could doubt John Owen's serious sex abuse
The victims said child protection measures must be strengthened after the Clywch report by Wales' Children's Commissioner Peter Clarke.
Welsh Education Minister Jane Davidson called the report "deeply disturbing" and said schools and education authorities had to improve procedures.
But one education official, David Matthews, said criticism of him was unjustified.
They responded to the report by Wales' Children's Commissioner into abuse by Owen at Ysgol Gyfun, Rhydfelen, Pontypridd, before he resigned in 1991.
Mr Clarke carried out the Clywch inquiry after Owen killed himself in 2001, the day before he was due in court to face five indecent assault charges.
Victims and parents
Victims' parents welcomed Mr Clarke's finding that they were "totally unaware of any matters of concern in respect of the conduct of John Owen".
In a statement, both victims and their parents said they were greatly concerned that there were incidents "as early as 1983 which should have alerted the authority to potential acts of sexual abuse by John Owen. The fact that no action was taken allowed him to commit criminal acts for at least a further 10-year period".
They called for a review of the "continued employment" of some people, and singled out David Matthews, a former district education officer for the former Mid Glamorgan education authority, and now director of education in Bridgend.
The Clywch inquiry was the first ordered by Peter Clarke
They also called on the WJEC (Welsh exam board) - who were also criticised in the report - to carry out a full review of child protection procedures.
In a statment on Thursday, the WJEC said that for many years it had "rigorous and
successful safeguards in place for the protection of children and young persons
in those areas of activity for which it does have direct responsibility for
care: these are, specifically, residential events in the expressive arts".
The WJEC has reviewed its policies, the statement added.
David Matthews, the former Mid Glamorgan education official criticised in the report, said many of the findings were unjustified, and the report was "riddled with inconsistencies and judgements based on opinions and not facts".
He said: "It may appear to everyone now, 13 years after the event, that the way the information obtained as a result of the investigation in 1991 was dealt with was unsatisfactory, but this was not the position back in 1991".
He said the 1991 allegations were much less serious than the ones which led to criminal charges 10 years later, and the police did not pursue them, but there was "little or no criticism of the police decision within the report".
Mr Matthews said the 1991 investigation "was conducted strictly in accordance with the local education authority's disciplinary procedures.
"Those procedures," he added, "were undoubtedly deficient by modern standards and perhaps even by the standards of the time. As the district education officer, I requested advice from county hall about the correct approach to dealing with the information obtained from the investigation but I did not receive a response.
Owen taught at the Pontypridd school from 1974 - 1991
"The terms of reference of Peter Clarke's investigation were to establish whether matters were investigated in accordance with good practice and guidance that was available at the time. My own involvement in the 1991 investigation satisfied this test."
He said Mr Clarke had stated the inquiry would be investigative rather then judgmental, and inquiry counsel Nicholas Cooke said he was "not interested in blaming people only in identifying where responsibility lay".
Mr Matthews said: "I believe in my case both of them have gone much further in this respect than they said they would and that they have done so unjustifiably."
Welsh Assembly Government
Welsh Education Minister Jane Davidson said it was essential schools and education authorities had clearer procedures in place, and that there "must be action" from the WJEC to improve its procedures.
"A number of organisations need to look carefully at the recommendations that the commissioner is making. They include the assembly government, other government departments, local authorities, WJEC, (curriculum authority) ACCAC and the police.
The National Union of Teachers said the situation had improved significantly since 1991, with clear guidelines for councils, training for teachers, the creation of the children's commissioner and the General Teaching Council for Wales.
The NUT praised the recommendation that local education authorities carry our investigations, rather governing bodies, but criticised the call for new independent tribunals as an "ineffective, expensive and unnecessary extra level of bureaucracy".
Anna Brychan, director of the National Association of Head Teachers Cymru said: "What is foremost in everyone's mind now is making sure that nothing like this is allowed to happen again."