Potentially dangerous soil from a Pacific Highway upgrade site has been given to property owners nearby, according to the state roads authority.
The Roads and Maritime Services (RMS) gave away top soil from the site which caused an outbreak of illness among road workers before Easter.
An unusual clay was uncovered on part of the Herons Creek to Stills Road section of the upgrade four weeks ago, causing five workers to vomit and feel nauseated.
The soil given away will now be tested as a "precautionary measure," RMS said today.
"Arrangements have been made with property owners to establish exclusion zones around the soil until test results become available."
It is understood the tests will continue tomorrow.
It was reported chemical waste was buried in the vicinity of the site after a 1980 truck crash.
That truck was carrying radioactive isotopes from Sydney to Brisbane as well as pesticide and foodstuffs.
The soil involved has tested negative to radioactive material, as well as pesticide, hydrocarbon, biphenyl and other metals.
The no-go zone set up on the highway upgrade site remains in place while investigations continue, RMS said.