AGL has suspended sales of coal ash from its Bayswater and Liddell power stations, while a downgrade from JP Morgan has also seen its share price dip.
Energy company AGL has suspended sales of coal ash and ash by-products from its Bayswater and Liddell power stations in NSW due to elevated signs of heavy metals in the product.
In a release on Thursday, the company said testing showed some of the coal ash from the Bayswater and Liddell power stations in the Upper Hunter region of NSW showed levels of chromium, cadmium and copper exceeding limits set by the Environment Protection Authority.
AGL's executive general manager of group operations Doug Jackson said while recent coal ash purchases had met customers' needs, sales had been halted as a precaution and a review is underway.
"Our external expert's initial advice is that the levels detected in the coal ash samples taken do not pose a risk to public or worker health and are unlikely to pose an unacceptable risk to the environment given the uses to which the coal ash is put," Mr Jackson said.
"We have asked those businesses that have purchased our ash to cease any further distribution of ash purchased from AGL and have provided assurances we will help them find alternative sources to minimise impacts on their businesses."
The Nature Conservation Council of NSW said AGL's admission highlighted the need to tighten environmental controls on the mining industry.
The company's share price was already subdued after JP Morgan Chase downgraded it from "overweight" to "neutral" overnight.
AGL shares dipped 1.99 per cent from a near five month high to close at $20.70 on Thursday.
Last month the company announced acting chief executive Brett Redman would have his position made permanent, following the departure of Andrew Vesey in August.