MARYSVILLE — The owners of the vacant Welco Lumber mill in Marysville have been working to fix code violations and make the site less attractive to squatters, according to city and fire officials.

A fire that broke out in an empty building at the site on Jan. 11 was one of many there since the mill closed in 2007.

The recent fire caused roughly $6,000 in damage, Marysville Fire Marshal Tom Maloney said Tuesday. There was not enough evidence at the scene to pinpoint exactly what caused the fire, he said. The investigation is wrapping up.

The former five-acre mill site on the Ebey Slough waterfront off of First Street has been a known hang-out spot for the homeless. The recent fire highlighted several ongoing code issues on the property, Maloney said.

The city and the fire district met with the owners to talk about what needed to be fixed. No fire-safety citations were issued, because the owners have been responsive, Maloney said.

The owners are adding lighting on the site and removing flammable debris, including plywood and lumber.

City Administrator Gloria Hirashima on Tuesday said Welco has been working to secure and clean up the site with an eye toward future use.

“Their intent is to lease or sell the facility,” she said.

The site is now a vacant lot with the shell of the old mill building still standing. Siding has been removed from several locations around the building.

The fire broke out about 10 p.m. and burned for about 30 minutes. More than two dozen firefighters were called to the scene.

Fire officials say they’ve received two or three calls a year for fires at the site, including an arson by local teenagers in summer 2010.

The mill and lumber yard operated for several decades.

Peter Garrett purchased the mill in the 1960s and it ran from then until its closing in 2007, according to Eric Erickson’s “Lumber and Shingles Business Index.”

In its heyday, the mill provided jobs to 150 people, producing cedar fencing and dimensional lumber that was used primarily in home construction.

Welco Lumber closed its Marysville mill with a drop in the area’s home construction market.

Marysville, like many other Snohomish County cities, has a rich timber history. In 1908, it had nine shingle mills and three sawmills in addition to jobs in the woods, according to historical accounts.

E.J. Anderson opened the first sawmill in Marysville in 1887, a stone’s throw from the Welco site.

Reporter Eric Stevick contributed to this story. Rikki King: 425-339-3449; rking@heraldnet.com.