The Rescue Board reported in the night to Sunday that their efforts to put out the smaller remaining fires continued. On Saturday, six fire engines and their teams were on site.

As part of the waste fuel production process, the plant uses a lot of wood chips. Those chips cover some 900 square metres, and firefighters were still working to put out the bits still burning or smouldering in the night to Sunday.

As the Rescue Board's Tiit Käit explained to ERR's "Aktuaalne kaamera" newscast on Saturday, sheet metal from the building's roof collapsed onto the wood chips, which is why the water never reached all of it.

Putting out the fire is resource-intensive, as the total floor space of the building is more than 7,000 square metres, Käit added. Some 6,000 square metres have been damaged by the fire.

CEO of Estonia's branch of Ragn-Sells, Rain Vääna, told ERR that it will be very difficult to get back to a point where they can continue production. The first order of business now is to estimate the damage done by the fire, he said.

"We can start estimating the damage once the Rescue Board allows us back in, but looking at it all from the outside, it's already clear that the damage is extensive," Vääna said. "We'll see what the exact sum is in the coming weeks, when expert assessments and the like can be carried out."

Investigators of the Rescue Board will try to determine how the fire got started. A month and a half a go, a fire needed to be put out in the same area.