Relatives were among those to sign the petition for a public inquiry

Five men and four women died and dozens were injured when the explosion demolished much of the factory in Grovepark Street on 11 May last year.

Relatives of the victims have already called for a public inquiry.

The Scottish Trades Union Congress (STUC) has now launched a petition supporting their call.

STUC assistant secretary Ian Tasker said people should not have to face death in the workplace.

You shouldn't have to fight for a public inquiry - they were at their work Rosemary Doyle Mother of victim

Mr Tasker said an inquiry would help the industry and the affected families.

He said: "Certain things might come out that will mean health and safety standards will be raised throughout Scottish, Welsh, English and Irish workplaces.

"The families feel that would be an appropriate way to help them go forward, knowing that the deaths of their loved ones had not been totally in vain."

Rosemary Doyle, whose daughter Annette died, said she still asks why her daughter was killed and what can be done to stop a future tragedy.

She said: "It is very upsetting because I think when nine people die at their work, along with the people with the horrific injuries, it should be automatic.

"You shouldn't have to fight for a public inquiry - they were at their work."

GLASGOW BLAST VICTIMS Margaret Brownlie, 49, Strathaven Annette Doyle, 34, Glasgow Peter Ferguson, 52, Kilbarchan Thomas McAulay, 41, Mount Florida, Glasgow Stewart McColl, 60, West Kilbride Tracey McErlane, 27, Possilpark, Glasgow Kenneth Murray, 45, Paisley Timothy Smith, 31, Johnstone Ann Trench, 34, Colston, Glasgow

Husband Joe Doyle added: "If there is a public inquiry into every question, the only thing we will end up with is the truth.

"That is all we are asking for and, through the public inquiry, that is what we hope to get - the truth."

Bill Spiers, of the STUC, said the call for an inquiry had the union's full support.

He added: "Families need to find out what happened, why it happened and can we stop it happening in the future?"

Last week, Scottish academics told BBC Radio 4's Face the Facts programme they had uncovered health and safety shortcomings and a public inquiry was vital.

However, in a statement, ICL Plastics and Stockline Plastics said the claims were "grossly misleading" and said the academics had formulated conclusions which were not based on reliable evidence.

Possible prosecution

The Crown Office said it is still considering a report into the blast.

That report by police, the Health and Safety Executive (HSE) and the procurator fiscal was handed over in May - a year after the explosion which claimed nine lives and left many more injured.

The Crown Office could either decide to prosecute the company or its director or, if there was no evidence of wrong-doing, call a fatal accident inquiry.