Firefighters battled a large mulch fire in Manor Township Friday morning.

No one was at Kreider Mulch, 356 Penn St., Washington Boro, when a passing motorist spotted the fire at around 4:45 a.m., said Chris Ditzler, chief of the West station of Blue Rock Fire Rescue.

The mulch pile is 20 feet high, about 100 feet wide and 600 feet long. Fire burned a 50-by-50-feet area of it, he said. “It was a deep-seeded mulch fire caused by hot mulch.”

Five tankers were used to haul water from a hydrant three miles away on Donerville Road. Firefighters extinguished flames until the mulch pile could be torn apart and cooled down, Ditzler said.

None of the 30 firefighters at the fire was injured. They brought the fire under control shortly after 6:30 a.m.

One thing strange about the fire was how little heat it generated, he said. No buildings are near the mulch pile and damage to the mulch was minimal, as most of it can be reused.

The mulch pile was built just before Thanksgiving. While hot hay is most dangerous in the summer, spontaneous combustion in mulch most often occurs this time of year, Ditzler said. The normally dry wood chips moisten from sap when the temperature drops.

“It spontaneously combusts from ground level below the pile,” he said. “Most times, the burn area is about the size of a wheelbarrow.”

Kreider Mulch routinely sprinkles water on the pile from its own pond to limit the temperature from rising enough to spontaneously combust, he said. But Environmental Protection Agency regulations stipulate mulch reaches at least 160 degrees to kill disease and bugs that could otherwise be passed on to customers’ mulch.

There is little room between that temperature and what could spark a fire, so mulch fires are “a fact of life,” Ditzler said. There have been numerous fires at the site before.

The fire struck a day after a compost fire in Elizabeth Township, Brickerville Fire Chief Jeff Strauss said.

Product from composting operations at the Flintrock Stables property on East Brubaker Valley Road was smoldering inside an open-air structure shortly after 8 a.m. Thursday.

Firefighters from Brunnerville, Lititz and Penryn helped Brickerville firefighters extinguish the hot spots.

Tankers hauled water from Hammer Creek on Old Pike Road to aid the effort. Firefighters contained the fire to the compost. The structure was not damaged.