Fifty-one people died when the Marchioness sank
They told BBC News Online why their campaign is so important - and why they will never give up.
John Perks is clear what he wants.
His son Stephen was 23 when he boarded the ill-fated riverboat, the Marchioness, for a party on the River Thames.
He never came back - a dredger collided with the Marchioness, sinking it and drowning 51.
Nothing short of ten years in jail for those responsible is Mr Perks's suggestion for "anything like justice" for his son.
Despite years of petitioning and protesting, he feels no one has taken full responsibility for the 1989 tragedy.
The official inquiry blamed the captains and owners of both vessels.
The dredger captain was tried twice for not maintaining a proper lookout, but the jury twice failed to agree a verdict. The skipper of the Marchioness died in the accident.
Mr Perks and his son Tony want company directors to take ultimate responsibility for accidents within their firms.
He said: "This sort of thing must be punished by a prison sentence. Fines get lost in balance sheets and...swallowed up by accountants.
"If a director faced jail, it would be more of a deterrent for them to get it right."
Eileen Dallaglio lost her 19-year-old daughter Francesca in the same disaster.
She said: "They [the boats' owners] paid out £189,000 in compensation. Not a lot for 51 lives and the devastation of 51 families. And, the coroner ruled they were unlawfully killed.
"That's why this campaign is so important."
Negligent
Company directors cannot be held accountable for deaths caused by negligent management under current manslaughter laws.
The group wants this changed and believes, with more effective punishments, it will make companies take the issue seriously.
Tom Byrne's son Gerard was 12 when a lorry reversed from its workplace and knocked him over.
The company - which had a turnover of more than £10m - was found guilty of two Health and Safety infringements and fined £50,000.
Mr Byrne said that was "a mere drop in the ocean".
He said flouting safety rules should be "as socially unacceptable as drink-driving and that can only be done if there are proper punishments to act as deterrents".
'Failed my son'
Seven people died in September 1997 when the Great Western express from Swansea to London collided with an empty freight train at Southall, west London.
Maureen Kavanagh's only son Peter - a successful 29-year-old lawyer - was among them.
"The law protected those who failed to protect my son," said Maureen, who also founded the Safe Trains Action Group.
Again, because no one person was ultimately accountable for health and safety provision, and because the law does not treat workplace deaths as it does deaths from crimes, no-one took ultimate responsibility.
She added: "The law is lacking. We have suffered the pain of loss and we go on suffering.
"We intend to see the law changed and won't go away until it is done."
In the past year, 434 people have been killed in work-related activities.
According to the Centre For Corporate Accountability, almost all could have been prevented had the firms involved complied fully with health and safety laws.
Anne Jones lost her son Simon, 24, in 1998 after an employment agency sent him to work in the hold of a ship with no training.
He was crushed by a heavy loader and died from severe head injuries.
The company owner was not punished - it was ruled he could not take legal responsibility when he was not even on board the ship.
Ms Jones said: "It is morally wrong - it is a parody of justice.
"Simon's death is a devastating loss but it's nothing short of a national scandal that more than 400 families every year have to go through the same thing."