The Victorian Environment Protection Authority is expected to file 12 air pollution charges against the Hazelwood power station operator, GDF Suez, over the Morwell coalmine fire.
The fire burned for 45 days in 2014, covering Morwell in smoke and ash. Residents were advised to leave by health authorities.
An inquiry found GDF Suez had failed to adequately prepare for the fire, which was sparked by a nearby bushfire, and that the fire probably contributed to increased deaths in the region.