Decomposing wood debris left over from decades of pulp and paper production has led to a persistent fire at the old pulp and paper mill complex at the south end of 28th Street in Hoquiam on land owned by Rayonier Inc.

“What we think is the cause is hog fuel,” said Warren Snyder, Senior Manager for Rayonier Advanced Materials. Hog fuel is wood material that can be used as boiler fuel in pulp and paper production. “Basically, what happens is it decomposes and decays over time, and heat and low humidity causes it to combust.”

Rayonier owns the land where the fire first reared up in late June.

Rayonier and International Paper operated a pulp mill and adjacent paper mill until 1992, when they closed the complex. About 600 workers lost their jobs in the closure.

“I know we had an incident June 30,” said Snyder. “We had contractors on site to uncover the hog fuel and apply water to the source.”

Aberdeen Fire Department Assistant Chief Rich Malizia said Hoquiam Fire was called to the scene on Sunday as the “spalt fire” flared up again, and were called back around 2 a.m. Tuesday. Some posters on social media reported flames visible several feet in the air.

Contractors from Brumfield Construction, who were called by Rayonier after the June fire, were called back to the location Tuesday morning to again dig up the problem areas.

“We’re going to set up a fire engine with water on a hydrant to monitor it,” said Malizia. He said the goal is for the contractors to dig out the burning wood waste and soak it down thoroughly in hopes that will prevent more flare-ups.

The fire at the abandoned site is not a threat to any structures, said Malizia.

Hoquiam City Administrator Brian Shay said he has been in contact with Rayonier about the property and has “made my voice loud and clear the city wants to see that site active and vibrant and serving our community for positive economic benefit, not a public nuisance.”

Snyder said Rayonier, which halted its Northwest operations years ago, has no current plans for the site. The property has been listed for sale for some time, but Snyder said, while there has been some commercial interest in the property, no serious attempts to purchase it have been made.

Snyder did not comment on a sales price. The assessor’s office shows parcels of the property owned by Rayonier Properties LLC with a total value of about $1.5 million.