Firefighters are reminding Ballarat residents to have their heaters serviced regularly.
It comes after Ballarat City staff responded to a gas leak from an old heating unit in Wendouree at 10pm on Sunday night.
Ballarat City station officer Morgan Mitchell said Ballarat residents had become more aware of the need to service heaters regularly but staff had still responded to several gas leaks from faulty or not serviced heaters so far this year.
According to Energy Safe Victoria, gas heaters should be serviced every two years by a licensed plumber.
"Having gas heaters serviced is one of those things that needs to be thought about," Mr Mitchell said.
Gas heaters can emit what is known as "the silent killer" or carbon monoxide (CO).
Carbon monoxide is invisible and does not have an odour and so if it reaches dangerous levels in a house, it can cause people to become very sick with headaches and even cause death.
The issue was brought to light when two young boys - Chase, nine, and Tyler Robinson, seven - were poisoned by the odourless fumes from an open-flued gas heater in their Mooroopna home, near Shepparton, in 2010.
Mr Mitchell said while there were sometimes indicators of a heater performer poorly, there were often not any signs.
It is possible for any gas heater, both older and newer models, to emit CO.
Mr Mitchell urged people to have their heaters inspected and serviced and if possible, to install a carbon monoxide alarm as an extra preventative measure.
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