WORK restarted on some sections of the Herons Creek to Stills Road Pacific Highway upgrade on Wednesday after preliminary test results were released.
Advice from an independent occupational physician and interim test results from chemical specialists have cleared the majority of the worksite and external sites of harmful contaminants.
Exclusion zones on the worksite where workers first displayed symptoms and part of an external site which received soil from the project will remain in place until a remedial action plan is identified and implemented.
Roads and Maritime Services (RMS) is working closely with a number of authorities to create an action plan to remove or contain affected soil so exclusion zones can be lifted.
Two external sites and a road side area near the Herons Creek School, where material from the site was used, have been cleared of harmful contaminants.
RMS and its contractor BMD Constructions are working with the owners of an external property where contaminants were identified to ensure an action plan is in place as soon as possible.
Low levels of organopesticides such as DDT and volatile fatty acids including acetic and propionic acid were identified by independent chemical specialists in an interim report.
The levels were extremely low and not considered to pose a health risk.
The findings were below EPA endorsed soil criteria for residences, schools and kindergartens.
The volatile fatty acids found in the exclusion zones are known as proprionic acid and can occur when residuals of sodium propionate remain in the ground.
In 1980 a truck carrying waste crashed on the Pacific Highway near the Herons Creek to Stills Road upgrade site.
Radioactive waste was disposed of offsite at a licensed waste facility in
accordance with EPA guidelines and other material was buried on site
including sodium propionate and pesticides (DDT).
The material was removed during the planning phase of the project but residual sodium propionate in the soil has caused fatty acids to evolve.
The acid can initially irritate if uncovered and exposed to the air. It then dissipates with time before becoming essentially unnoticeable. There are no long-term health effects associated with exposure to these fatty acids.
Finalised reports will be released next week on the RMS website.
Safety of the site, for workers and the general public will remain the NSW Government’s top priority while this investigation is continuing.