The state's watchdog believe a vast majority of the plastics arrived from interstate.
EPA chief executive Lee Miezis said steps are being take to ensure there's no risk within the stored warehouses.
"Our officers are out inspecting sites today and we'll continue to work hard – using our stronger regulatory powers — until we're certain we've found every site in Victoria," he said.
"We will not allow unacceptable risks to Victoria's community or environment from pollution or waste."
"Although the operators of REDcycle did tell us about some of the sites, intelligence from logistics companies and others is assisting EPA's investigations.
"If you have any of these soft plastic wastes at your warehouse, we need to know.''
The EPA believes more sites are storing mass amounts of soft plastics suppose to be part of the state's recycling scheme.
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