Emergency officials considered evacuating the town of Morwell, in Victoria's Latrobe Valley because of the acrid smoke billowing from the fire at the Hazelwood open cut mine.

The coal fire has been burning for 11 days, creating toxic conditions for the Country Fire Authority firefighters battling the blaze and local residents.

Houses, cars, gardens and even schoolyards are covered in a veil of soot.

Craig Lapsley, the Emergency Services Commissioner, confirmed on Wednesday that the State Government considered evacuating the whole town last weekend.

Sorry, this video has expired Latrobe Valley's air quality goes from bad to worse ( Cheryl Hall )

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 2 minutes 46 seconds 2 m 46 s Coal mine smoke drives primary school students out of classrooms ( Rachael Brown ) Download 1.3 MB

"We had a very good look at that. (We decided) it wasn't appropriate," he said.

He was asked what air quality triggers would necessitate an evacuation.

"You'd certainly need to be above 30, 40 or 50 parts per million (of carbon monoxide)," he said.

"We've seen a couple of spikes in a couple of detectors but they haven't been sustained and it needs to be sustained."

Air quality levels today are listed as being good.

More than 200 students from Commercial Road Primary School have been billeted out to three schools in nearby Moe because of the poor air quality.

Fighting the Hazelwood mine fire What makes extinguishing a brown coal fire difficult?

Coal is effectively a ground fire that burns under the surface.

Coal is effectively a ground fire that burns under the surface. What is the best way to put out the fire?

Constant and continuous application of water onto the burning face to cool the coal.

Constant and continuous application of water onto the burning face to cool the coal. How long do they expect it to take?

CFA, MFB and support agencies will remain on scene for as long as required to extinguish the fire.

CFA, MFB and support agencies will remain on scene for as long as required to extinguish the fire. How long did that take to extinguish a similar fire in 2006?

Emergency Services were involved for about 10 days. The 2006 fire was not as extensive as this one.

Emergency Services were involved for about 10 days. The 2006 fire was not as extensive as this one. How does it compare to this fire?

The current fire is in a disused part of the mine which was originally dug in the 1960s. Currently, this fire is having no impact to coal for power supply.

The current fire is in a disused part of the mine which was originally dug in the 1960s. Currently, this fire is having no impact to coal for power supply. Source: Traralgon Incident Control Centre

Teachers are restricting students' physical activities, so they don't get puffed and adults, like asthma sufferer Mick Graham, are also struggling.

"The last couple of days I haven't been able to work, blinding headaches, eyes feel like they're on fire," he said.

"My throat feels like the skin's been pulled out of it."

Another resident says everyone in her house is suffering from headaches, sore throats and impaired breathing.

Even the family pets are suffering.

The mine fire is brewing a cocktail of gases including carbon monoxide, nitrogen dioxide and sulphur dioxide.

Melbourne University air quality expert Dr Robyn Schofield explains children, the elderly, pregnant women and those with existing medical conditions are most at risk.

"The smoke is a great irritant to start with," she said.

"Carbon monoxide is a wee bit different because it's silent. You can't smell it; you don't know you're being exposed.

"If you start to get headaches then you should seek medical advice."

Victoria's Chief Medical Officer Rosemary Lester does not expect there will be any long-term health effects.