The Calf Canyon Fire was caused by a “pile burn holdover from January” that was started by the Santa Fe National Forest Service, officials said on Friday.

The blaze later merged with the Hermits Peak Fire – also started by a federal prescribed burn – to become the largest fire in the state’s history, burning hundreds of homes and displacing thousands of New Mexicans.

“The pain and suffering of New Mexicans caused by the actions of the U.S. Forest Service – an agency that is intended to be a steward of our lands – is unfathomable,” Gov. Michelle Lujan Grisham said in a released statement.

The Calf Canyon/Hermits Peak Fire has burned more than 312,000 acres as of Friday morning and is 47% contained. More than 3,000 personnel are battling the blaze that has destroyed 761 structures, including nearly 350 homes.

On January 29, Santa Fe National Forest crews concluded the Gallinas Canyon Wildland Urban Interface pile burn.

Pile burns are when agencies set fire to debris from earlier thinning and reforestation projects.

Fire investigators found that on April 9, crews responded to smoke in the vicinity of the pile burn.

The region had seen at least three snow events before the 1.5 acre Calf Canyon fire emerged.

The Forest Service is calling the event a holdover fire, or sleeper fire – “a fire that remains dormant for a considerable time.”

Crews monitored the small Calf Canyon Fire and lined the blaze until 10 days later on April 19, when the fire “reignited and escaped containment lines.”

On April 22, high winds caused “significant fire spread,” and Calf Canyon merged with the Hermits Peak blaze to east.

“The Santa Fe National Forest is 100 percent focused on suppressing these fires with the support of the Type 1 incident management teams who are fully prepared to manage complex, all-risk situations,” SFNF supervisor Debbie Cress said. “Our commitment is to manage the public lands entrusted to us by improving the forest’s resilience to the many stressors they are facing, including larger, hotter wildfires, historic levels of drought, rising temperatures, and insects and disease.”

On May 20 the U.S. Forest Service paused all prescribed burns nationwide on forest lands in the wake of the New Mexico disaster.

Lujan Grisham said the Forest Service’s admission marked “a first step” toward the federal government taking full responsibility for the blaze which, aside from the personal toll, has cost state and local governments millions of dollars.

“I appreciate the U.S. Forest Service assuming responsibility for the federal actions that caused this terrible crisis,” she said, adding that the agency must “take a hard look at their fire management practices and make sure they account for a rapidly changing climate.”

“New Mexico and the West must take every precaution to prevent fires of this magnitude from occurring, especially as precipitation levels continue to decrease and temperatures rise,” Lujan Grisham said.