But the state-owned operator says it is working to be a better organisation following a damning report into the power plant's safety failings.
Almost half a million households were left without power after pieces of metal weighing two tonnes blasted out of a turbine at central Queensland's Callide Power Station in May 2021.
The power plant, which still has one unit offline following the explosion, has again come under scrutiny after a sub-contractor was injured at the site on Friday night.
He suffered burns to his feet while working in the boiler house.
Operator CS Energy's CEO Darren Busine said employees were told to stop working and a safety reset was carried out the following day.
"It is not acceptable that somebody got injured on Friday night," Mr Busine told Queensland budget estimates on Tuesday.
CS Energy also confirmed another unit at the power plant was brought offline due to a technical fault in a battery charger recently.
The operator said it was investigating why it occurred given the C3 unit had only recently been brought back online and was still within its warranty period.
The incidents occurred after forensic engineer Sean Brady's independent report found Callide staff had longstanding concerns about an unsafe work environment before the 2021 explosion.
The Mining and Energy Union claimed the two incidents had raised fears among workers of another explosion, saying "enough is enough".
"We have members still nervous following the C4 incident. The workers on site have lost all trust in CS Energy management," the union's Queensland branch vice-president Shane Brunker said.
"These events should be foreseen and should be preventable."
Energy Minister Mick de Brenni said the spending on an independent report was CS Energy's choice. (Darren England/AAP PHOTOS)
The union called on the government and shareholding ministers to intervene in CS Energy to prevent further "safety failures and ongoing poor maintenance decisions".
CS Energy management remains steadfast its plan to become a "safer, better and highly reliable" organisation is the right one in the wake of the Dr Brady findings and subsequent incidents.
"I take responsibility to the organisation and to our staff very seriously," he said.
The Miles government has appointed two advisors to CS Energy and launched a review of its business structure following the report.
The budget estimates hearing also revealed the cost of the Brady report totalled $10.4 million.
However, the energy minister said spending that amount was not the government's choice but rather a decision made by the state-owned operators.
"CS Energy and its legal representatives were responsible for commissioning the Brady... investigation," Mick de Brenni told the hearing.
"They set the scope for the investigation, entering into the financial arrangements for and inevitably paying for this report as is their operational responsibility."
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