The potential exposure of more than 100 Water Corporation employees to asbestos must be investigated in an independent inquiry, the West Australian State Opposition says.
Some 138 employees and contractors were potentially exposed to white asbestos during renovation work at the Minnivale reservoir in the Shire of Dowerin between April and September this year.
The white asbestos was contained in fascia panels and sealant used in building work at the site.
Water Minister Mia Davies told Parliament the corporation was investigating the incident, and the internal probe would be overseen by the safety committee of its board of directors.
"Preliminary findings suggest Water Corporation's processes for managing asbestos at the reservoir site were not adequate," she said.
"It appears that the necessary checks for asbestos were not made at key stages of the project delivery."
Ms Davies told Parliament the incident and Water Corporation's response was being monitored by Worksafe.
"Worksafe has advised that it will review Water Corporations progress towards establishing a plan to address asbestos management across the organisation and this feedback is due at the end of November, and again at the end of January," she said.
"In the interim, the Water Corporation board has asked for a number of processes to be reviewed, including the asbestos register and management processes as well as changing project management and design processes to ensure that it doesn't happen again."
Workers 'unhappy' with internal review
But the State Opposition said it was not satisfied, with their spokesman for water, Dave Kelly, calling for an independent inquiry.
"What the workers are telling me is that they are not happy for the Water Corporation to be in sole control of this investigation," Mr Kelly said.
"The Government should appoint someone from outside the Water Corporation, someone who is not a government employee, who would have the trust and respect of the people who have been exposed, and allow them to conduct the investigation."
Mr Kelly said it was the most significant asbestos exposure in recent years, and it was due to a failure to identify asbestos at the site.
He said asbestos was noted on detailed plans included in the tender documents for the work, but not listed in the risk control documents.
"So it's not an accident, it's a failure by the Government to protect its own staff and contractors," he said.
"And rather than have the Water Corporation and the Government protect itself from issues of legal liability, they should appoint someone independent who can look at this in a way that would give the victims some confidence that justice will prevail."
The Water Minister told Parliament the asbestos panels were dumped at the Northam landfill facility in April and May this year.
Ms Davies said it appeared the asbestos had been buried under other waste material.
The Department of Environmental Regulation is investigating and will advise the Water Corporation of any further action required.
It is also assessing the Minnivale reservoir site where dust from the renovation work was deposited.
Tests are being conducted to determine if asbestos is present at the site.