ShareThisVENTURA, Calif. - An unusual situation involving very hot weather and a large pile of composting manure apparently triggered a fast-moving fire that was raging through brush and endangering hundreds of homes Wednesday in California, officials said.
The Ventura County Sheriff's Office of Emergency Services said in a news release that the Guiberson fire, which had devoured an estimated 9,700 acres by midday Wednesday, "was started due to manure spontaneous combustion from a local ranch." A call to the office seeking additional information was not immediately returned.
Ventura County Fire officials, however, said they have not confirmed that information from the sheriff's office.
But an official with an Oxnard, Calif. company that composts huge quantities of agricultural and landscape green waste to turn it into potting soil and other soil amendments said it is not uncommon for the decaying material to start burning. That is why fire codes strictly limit the size of compost heaps and require that their temperatures be closely monitored.
"Our regulators require that we turn and aerate the pile to cool it down when the (core) temperature reaches 160 degrees We monitor the temperatures of those every day," said Dave Green, vice president of sales and marketing for Agromin Inc. "Any time a pile gets over 12 feet high, the core temperature of that could be one which could cause spontaneous combustion."
Agromin collects agricultural vegetation waste from many local farms and ranches, as well as grass clippings, leaves and other landscape materials disposed of by area residents. It does not compost manure, Green said.
But many growers and other recyclers do to turn it into soil nutrients, said John Krist, chief executive officer of the Ventura County Farm Bureau.
"I mean, I'm not an expert in this area, but I know decaying organic material gets warm. That's why compost piles steam on a cold morning," Krist said. "It's just a product of microbial action. I think I've heard of compost piles bursting into flames, but I was not aware that it could get to this level."
Compost piles can be no more than 12 feet high and 25 feet wide, Green said. He said beneficial bacteria creates heat as it works to break down composting material.
"Nature really doesn't care what the material is," he added. "It's trying to do the same thing no matter what."
The fire broke out about 10:45 a.m. Tuesday and was spread quickly by fierce winds and temperatures that topped 100 degrees. It spread a pall of ash and smoke over most of Ventura County, and forced officials to order the evacuation of about 400 homes.
(Jim McClain is a reporter for the Ventura County Star in California.)
