The Environmental Protection Authority has issued the owner of an illegal waste dump south of Kaniva with a show cause notice.
In a statement on Thursday, the regulator said it asked the Lemon Springs property owner why it should not take over the management and clean-up of the waste.
It said it had a "growing intolerance of the slow rate of progress" since issuing the owner, Graham Leslie White, a clean-up notice.
It did this in September, after Mr White had been released from prison for serious firearms offences.
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"Further action will be determined once the owner... has been given an opportunity to respond. Meanwhile, EPA is on site regularly and progressing its investigation," the organisation said.
"While recent testing continues to show no signs of contamination to groundwater, exploratory excavation works show the 20 dispersed waste dumps contain a volume of waste of up to 8,000 cubic metres of solid and liquid waste.
"(The) EPA estimates of this volume, three to five million litres, which is likely to contain solvents, hydrocarbons and associated liquid waste.
"The total area covered by the dump sites is around 2 acres of the 1,400 acre property.
"All excavated waste has been placed in a secure and bundled area on the property. This waste will be removed from the site and taken to an appropriately licensed facility by the end of November in accordance with transport of Dangerous Goods legislation."
EPA north west regional manager Dr Scott Pigdon said testing continued to show the groundwater had not been contaminated by the waste.
The organisation will stage another community meeting at Kaniva Shire Hall between 5 and 6.30pm on Thursday November 21.
It said people could register to attend by emailing firstname.lastname@example.org.
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