The cells were covered with a thick layer of clay to contain the smoke and odour, which the EPA warned may need to be uncovered to extinguish the fire, further intensifying the odour and possibly releasing smoke. Loading Barro Group spokesman Steve Murphy said an exhaustive process, during which 102 holes were drilled across the site, was undertaken to find the fires. “This isn't a quick process, identifying the fires required drilling into the ground and using thermal monitoring and heat signatures," Mr Murphy said. "There are three main ways we can put this out; we can drill down and flood the cell with water; we can starve it of oxygen; or we can dig the whole thing up."

Mr Murphy gave no indication as to which option was being favoured, but said it will take a considerable amount of time to extinguish the fires, regardless of method. "We're not talking days, we're talking several weeks, if not more," he said. "We understand residents will want to know exactly how long this is going to take, but we're going to make sure this is done right." "What we do need to say is that there's absolutely no toxic chemicals burning. We understand residents are concerned about the strong odours and we've apologised for that, but we stringently check each truck that comes in." It's little consolation for residents who have endured suffocating odours for months.

Mark Pepper lives in a property neighbouring the site and said the smell has been unbearable. Residents say they've been choked by a "toxic" smell for months. Credit:Jason South “We live in a straight line to the landfill, there’s not even 500 metres from our front yard to the tip,” Mr Pepper said. “We get up in the morning, open the front door and we’re hit with a blast of this toxic smell. “We first noticed it in late October and then it really kicked in come November."

"Over the December and January period when it was very hot and windy, we’d have to shut our doors, close the floor vents, make sure the windows were closed and stop running the air conditioner.” Another resident, Siobhan Brister called it a horrifying experience. “We were absolutely horrified when we found out there was an underground fire burning so close to our homes,” Ms Brister said. “It’s an incredibly toxic odour. We can’t use our evaporative cooling air conditioner because it sucks all the air in and makes it worse. “I’ve even had to start drying clothes in the tumble dryer because I can’t hang them out without the smell getting into them."

In January the EPA installed air monitoring units in the homes of two residents neighbouring the site following the complaints, which rated the area’s air quality as good. Barro has continued to monitor the air quality, but Mr Pepper still has concerns. Extinguishing the fires will take several weeks. Credit:Jason South “I have a three-month-old baby I’m concerned about breathing this in. I know they tested the air quality for a little while and said it was good, but there’s still something in the air making this foul smell and nobody knows what it is," Mr Pepper said. "What’s burning? What chemicals are putting out this odour?

“I’ve had a dry cough, an irritated throat and nausea. None of this should’ve happened and it shouldn’t have continued.” In December the EPA issued Barro with a clean-up notice, requiring ongoing air quality monitoring and publication of the results, as well as actions to keep the community informed. It also requires it to undertake a risk assessment and provide plans to the EPA that show how it will prevent further hotspots. The group was also issued an official warning for failing to notify EPA of the incident immediately. Mr Murphy said it's the first time a hotspot has been discovered at the site and that the company was at a loss to explain how two sprung up at once.

"Until we get down there it's difficult to tell. It could be something as simple as oxygen, friction and cardboard creating the perfect ingredients," Mr Murphy said. Loading The landfill is no stranger to controversy and was the subject of a drawn-out legal battle before it even opened. In August 2010 Barro Group riled locals when it first flagged the proposal to turn the old quarry site into a landfill. The proposal received more than 650 objections and was knocked back by the Brimbank Council and VCAT.