EPA will begin collecting formal witness statements this week as part of its ongoing investigation into the Hazelwood mine fire.
Chief Executive Officer Nial Finegan said investigators were at a stage in their investigation where they would be seeking formal statements from operators at the site.
"It’s important we keep people informed of what we are doing and why we are approaching people at this time," he said.
"The ongoing investigation is looking at air pollution and environmental hazards caused by the Hazelwood mine fire and gathering evidence is part of our normal investigative process.
"Information gathered will help the EPA determine whether any offences have been committed under the Environment Protection Act."
Mr Finegan said the Hazelwood mine fire was an unprecedented event that had a prolonged impact on air quality and the community.
"In addition to our investigation, EPA will continue to undertake ongoing inspections at the site to ensure any environmental issues that may arise are dealt with."
"The EPA is absolutely committed to regularly meeting and working with the community, council and other stakeholders to ensure that the results of ongoing air monitoring are widely available and understood."