Authorities in central Idaho say they have no estimate for when fires in several large mulch piles north of Hailey will be extinguished.
The Twin Falls BLM District says the fire burning about five miles north of Hailey is about four acres in size.
The U.S. Bureau of Land Management says the size of the compost piles and the amount of heat being generated is making it difficult to fight the fires.
"Slow but steady progress is being made on the Ohio Gulch Fire," a press release stated. "The compost piles continue to produce significant heat and firefighters are using water and foam to cool the piles as heavy equipment breaks them down."
Smoke remains a factor to the surrounding community of Hailey. People who are sensitive to smoke should take precautions.
The compost piles caught fire on Wednesday at Wing Compost Co.
Excavators and a bulldozer have been breaking up the piles in an attempt to help extinguish the fires.
The cause of the fire is undetermined. No structures are threatened.