Further tests at 40 houses near Holden's Elizabeth site went ahead yesterday, following tests carried out in August last year.
The ABC reports that the tests on the crawlspaces underneath 40 homes are to compare levels with results announced last year, which found trichloroethylene and perchloroethylene (TCE and PCE) present in low, acceptable levels.
Accessing and using the area's bore water is not recommended, though audit results found the "risk to residents is well within the acceptable levels".
Yesterday's tests were done to determine seasonal variations in the chemicals. The contamination was first discovered in December 2011.