In 2014, The Newcastle Herald revealed in a joint investigation with Macquarie University that, despite official assurances the area was safe, there were alarming levels of lead and other heavy metals found in homes and public places at Boolaroo, Speers Point and Argenton.

The operation to clean up the Pasminco area was said to be among the largest in Australia's history. It involved gaining NSW government approval in 2014 to place 1.9 million cubic metres of contaminated material into a 45-metre-high containment cell in a 19-hectare are on the site.

The site was scraped back to the rock to remove contaminated material after the Herald's investigation found that a state-sanctioned clean up of toxic land two years earlier at north Lake Macquarie had failed.

Dangerous levels of heavy metal pollution were found across three suburbs, a catalogue of government failings and residents feared sick from past exposure.

Lead experts said exposure to the contaminated soil and dust could cause sickness, brain damage, behavioural problems and retardation in children.

More than 130 soil and household dust samples were taken from homes, sports fields, parks and schools in Boolaroo, Speers Point, Argenton and Teralba as part of the joint Herald and Macquarie University investigation.

Results, analysed at the National Measurement Institute, found lead in soil more than 14 times the Australian residential standard of 300 parts per million (ppm) and arsenic inside a home almost 300 percent above the safe level.