A New York resident making s’mores in their backyard is suspected of accidentally igniting a series of wildfires over the weekend that swept through hundreds of acres of the Pine Barrens region of Long Island, authorities said Monday.

Suffolk County Police Commissioner Kevin Catalina said the “operating theory” is that a fire was started at about 9:30 a.m. ET Saturday when a resident used cardboard to start a fire to make s’mores, a confection that includes toasted marshmallows and chocolate sandwiched between graham crackers.

“The individual making s’mores was unable to get the fire lit due to the winds, but they used cardboard to initially light that fire,” Catalina said during a news conference on Monday. “The person subsequently discovers that the fire does ignite in the backyard area and all goes up in fire.”

Catalina said the initial fire was extinguished by 10:30 a.m., but investigators believe embers blew about an eighth of a mile southeast of the s’mores fire and started a second blaze just before 1 p.m. in the Manorville community of Suffolk County.

Northwest winds of up to 45 mph quickly spread embers from Manorville, igniting a fire in Eastport and another fire in the publicly protected Pine Barrens region of West Hampton, according to Catalina.

“It was initially reported that there were four separate fires, or reported at one time,” Catalina said. “All of those fires are in a direct line with the strong northwest wind that was blowing that day. And it is believed that the embers from each fire traveled and continuously started more fires. So that is the operating theory right now.”

Catalina said the department has 25 arson investigators probing the blaze to determine the exact cause of the fire, but added, “So far, our investigation is pointing strongly toward an accidental origin for Saturday’s fires.”

The combined fires burned about 600 acres of wildland and prompted New York Gov. Kathy Hochul to declare a state of emergency. At least two commercial structures were damaged, officials said.

Suffolk County Executive Edward P. Romaine said Monday that two volunteer firefighters were injured battling the blazes on Saturday, with one being airlifted to Stony Brook Hospital in Stony Brook with second-degree burns to the face. The other hospitalized firefighter suffered a non-life-threatening head injury, Romaine said.

The fires in Suffolk County are “100% contained,” Amanda Lefton, the acting commissioner of the New York State Department of Environmental Conservation, said. Firefighters will remain on-scene over the next few days to prevent any spot fires from igniting, Lefton said.

Romaine said that at one point during Saturday’s blazes, firefighters feared the blaze would jump Sunrise Highway and spread into the more populated communities of Suffolk County.

He said the fire was fueled by hundreds of dead pine trees in the Pine Barrens region.

“Without the combined efforts of everyone involved, we would not have been able to stop this fire,” Romaine said. “This was a fire that could have been far more serious than it was.”

More than 600 firefighters from 80 volunteer Suffolk County fire departments responded to the blaze, battling flames and smoke visible from as far away as Connecticut, Romaine said.