A U.S. Forest Service investigation into the origin of last summer’s $9 million Horsethief Canyon wildfire points repeatedly to a burn barrel at a house where 76-year-old James Anderson Jr. was staying.

A report concludes the fire was human-caused during a time when a partial fire ban was in effect in Teton County. It began on private property where trash in the barrel was lit at 6 a.m. the morning of Sept. 8, the investigation report says.

The News&Guide obtained the documents after requesting them under provisions of the Freedom of Information Act. The report includes a hair-raising account of hikers barely escaping the blaze as it chased them uphill and burned their trail.

Their story helped investigators pinpoint the fire’s origin.

A “fire investigation report” signed by Jackson Hole Fire/EMS Marshal Kathy Clay and included in the federal probe called the fire accidental.

 “The fire escaped the barrel, which had rusted through around the bottom creating a significant gap at the base of the barrel allowing for embers to fall down,” her report said.

The fire blew up into a conflagration and was called in to emergency responders at 2:48 p.m. It went on to burn 3,373 acres, much of it on the Bridger-Teton National Forest.

It threatened the east side of the town of Jackson. Residents there were on evacuation alert for several days.

The report runs 126 pages. Most names, including that of James Anderson Jr., were blanked out in the copy provided to the News&Guide.

The Forest Service did not provide 20 pages, claiming it was exempt under the law.

The name Anderson appears several times in the documents where it was not redacted. The redacted documents do not explicitly name James Anderson Jr. as the subject of several interviews with the person who said he lit the trash barrel. But it is apparent from the context of the investigation, family statements and other news stories that James Anderson Jr. was the focus of the probe.

The documents provided by the Forest Service include several agencies’ reports, and at various points investigators refer to their person of interest as the home or property owner.

However, family members have said the younger James “Jay” Anderson III, whom the Teton County Clerk lists as the property owner, is not the subject of the investigation into who started the blaze and was not in town at the time it began. The elder Anderson was staying at the property at the time.

One of the first firefighters on the scene clued into the fire’s origin quickly. When he or she sprayed the rusted barrel with water, it was “noteworthy” that the barrel hissed and steamed, the report said.

“My immediate impression was that the barrel was far hotter than it should have been if it were simply heated by the combustion of the surrounding fuel load,” the firefighter’s statement in the report said.

“Given this information [one of two firefighters there] requested the Incident Commander ... reassign her to investigations,” the report said.

Firefighters found an unnamed person trying to stop the fire’s spread. Because of the danger, that resident was told to stop and go home.

An interview followed, during which a person told investigators he started the fire at 6 a.m. in the burn barrel with twigs, shrubs, pages of paper, architectural drawings and a lighter. A plastic composite shelf was part of the material.

He told one investigator he checked the barrel one hour later and “nothing was there.” He went on with the day’s activities, including watching football and having lunch before seeing smoke through a window. He went out to find a growing fire and tried to fight it with a shovel, the documents say. Attempts to call 911 failed.

The fire was within six feet of the house and in line with a dog’s “invisible” electric fence. When he went outside, 3-year-old border collie Lucy was missing.

A partial fire ban in effect throughout the county prohibited burning except in a container located in a cleared area 10 feet in radius and including a spark arrester. Spark arresters — typically a metal screen — prevent sparks from escaping a chimney.

“The barrel, in which [redacted] set the debris on fire, was compromised at its base (having rusted completely through) and no ‘device’ designed to prevent the escape of sparks or smoldering debris was observed by the firefighters and investigators assigned the origin area,” the report said.

Investigators also interviewed three hikers coming out of a canyon above the fire’s origin.

“We rounded a corner and saw the fire, about 25-30 [feet] from a home, and about 50-60 feet from us,” one wrote. “It was [burning] in a straight line, heading diagonally up the butte right above Elk Ave. We all figured our best option was to start sprinting up the hill.
“About 5 minutes into running I dialed 911” one hiker wrote. The call was at 2:58 [pm], so we must have seen smoke at 2:45 [pm] or 2:50 [pm].

“We tried running up & away & across the butte. As we ran, we felt the heat of the fire & it was following right behind us,” the witness wrote.

The group reached safety at the top of the butte, but only after running for 10 minutes, according to another written statement.

Those statements, along with hikers’ photographs and a study of the burn pattern, led investigators back to the burn barrel.

Investigators found nothing else that might start a fire, such as signs of lightning strikes or fireworks.

“Based on evidentiary findings and eye-witness statements, Forest Service has determined the Horsethief Fire was ignited when [redacted] willingly set fire to debris in a faulty burn barrel located on his property,” the investigation says. “[Redacted] left the fire unattended. In his absence, hot ash fell from the base of the barrel, igniting dry vegetation which burned beyond [redacted’s] span of control.”

— Emma Breysse contributed to this story.