Road workers have become sick after finding what could be a radioactive dump site during upgrade work on the Pacific Highway.
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Roads and Maritime Services (RMS) has stopped work on the Herons Creek to Stills Road Pacific Highway upgrade site, south of Port Macquarie.
The upgrade's project manager, Bob Higgins, said the workers became sick after unearthing a clay-like material.
Mr Higgins told the ABC a number of workers felt nauseous and some vomited when they were close to the material.
A truck carrying radioactive waste from Sydney's Lucas Heights nuclear reactor was involved in a crash on that stretch of highway in 1980 and the waste was subsequently buried near the crash site.
Independent chemical specialists are onsite collecting samples for testing. No determination has been made about the potential source of the suspected contamination.
“Tests should be able to confirm if there is a chemical present, what it is and how to remove it so work can restart safely,” a RMS spokesman said.
“An area of known contamination was identified earlier during the project development phase.
“This material was assessed and disposed of offsite to a licensed waste facility in accordance with EPA guidelines.
Work will not start within the exclusion zone until all relevant testing and approvals from authorities have been received.”
The discovery has prompted environmental outrage.
"The government knew that highly radioactive waste was there somewhere, but presumably just hoped it would never resurface," Greens MP and environment spokeswoman Cate Faehrmann said. "The presence of this dangerous material should have been considered prior to the upgrade with a full management plan – that's no easy task and requires very careful planning.
"Why weren't the workers prepared for the discovery of this waste? Why were road workers even there?
"There is potential for serious long-term health impacts from exposure to radioactive waste. The fact that some have reported to have vomited during the discovery is extremely worrying.
"How was the environmental impact statement signed off in the first place when there was a chance of disturbing radioactive material?"