Council workers moved through Gilba Road, Palm Street and Oramzi Road on Tuesday ripping out the evidence of Girraween's tree deaths.

Tests run by the Office of Environment and Heritage last year found that the tree deaths in parts of Girraween were likely the result of the presence of a herbicide in the affected plants known as metsulfuron methyl.

Metsulfuron methyl is the key ingredient of the herbicide Escort® XP produced at the DuPont factory on Magowar Road, just metres from where the council workers removed the dead trees this week.

The state authority has not named DuPont as the source of the contamination but did say the chemical it found in the trees was a "substance that is manufactured locally". The OEH would not give a date for when their investigation would be completed.

"The investigation is ongoing but drawing to a close," an OEH spokeswoman said.

"No regulatory decision has been made as yet. The possibility of a prosecution is still a potential option."

Girraween residents said they hoped DuPont, who they believed were responsible for the die-back of plants, were made to pay for the incident.

"They have to do something about it," one resident Gilba Road said.

Another Gilba Road resident, Ray Tavener, said some the damage done to his garden could not be compensated.

One of the dead trees he removed from his front yard had been planted for his daughter when she was a baby.

"It had been there since she was a baby, it had grown with her, it was a sentimental tree," he said.

A DuPont spokeswoman said the company would not speculate on the outcome of the OEH investigation.

"Our own investigations have shown that the plant operates to the highest emission control standards," she said.

"The DuPont plant at Girraween has been a responsible member of the local community for more than 40 years, conducting its operations to the highest environmental standards and without any impact to human, animal or vegetation health."

¦ DuPont has encouraged anyone who is concerned to contact plant manager Tony Azzopardi on 0418 113 953.