Newcrest Mining Ltd., being taken over by Newmont Corp., is facing an investigation by Australian environmental authorities following complaints of dust pollution affecting residents near one of its largest gold mines in New South Wales.

The state’s Environment Protection Authority said it would implement additional measures to mitigate dust emissions and carry out further testing on the company’s Cadia mine to assess health risks to the community, after it found previous actions to manage pollution were not effective.

“Industry has strict obligations to meet clean air standards and currently Cadia appears to be falling well short of our expectations,” NSW EPA Chief Executive Officer Tony Chappel said in a statement on Monday. “Everyone in NSW has a right to clean air no matter where they live.”

Newcrest, Australia’s top gold producer, was fined A$15,000 ($10,000) in August last year for failing to effectively mitigate dust pollution at Cadia, which is forecast to produce at least 560,000 ounces in fiscal 2023. The bullish prospects for the mine helped draw acquisition interest from US gold giant Newmont, which sealed a near-$20 billion deal to buy the Melbourne-based company earlier this month.

Newcrest has until Tuesday to respond to the investigation, the authorities said.