EVERETT — Much higher levels of contamination were found during the Kimberly-Clark mill demolition. Arsenic and other heavy metals turned up in ground up concrete being used for fill at the 66-acre site on Port Gardner.

The company and state officials promised city leaders on Wednesday that even though clean up will take extra steps, and perhaps more time, development on the land will not have to be limited to industrial uses.

The City Council asked state Ecology officials and Kimberly-Clark to answer questions of whether Kimberly-Clark was shirking its cleanup obligations. Concerns from residents and council members included possible health risks and whether the land would only be fit for another factory.

“I want to make it clear that no final cleanup plans have been made yet in relation to the Kimberly-Clark site,” Ecology department section manager Barry Rogowski said.

More than 700 people lost jobs when Dallas-based Kimberly-Clark Corp. closed the Everett mill in April 2012. Demolition began last summer.

While demolition of the factory buildings is expected to end this month, cleanup of the land could take three years or more. Some of the decontamination work could take place at the same time as redevelopment. Removing mill-related pollutants from East Waterway is more complicated and expected to take much longer.

Studies to decide what cleanup steps to take — and how much they’re likely to cost — are at least a year or two away. The state will accept public comments before hammering out a final cleanup order with Kimberly-Clark.

Kimberly-Clark and state officials always understood they were likely to find unexpected contaminants as the mill buildings, some of them 80 years old, were dismantled.

That scenario popped up in April, when debris samples tested higher than expected for arsenic, other heavy metals and petroleum products.

Separately, Kimberly-Clark in May received a warning notice over excessive demolition dust.

Until recently, Kimberly-Clark had only one water truck stationed at the demolition site to keep dust from blowing into the air. The Puget Sound Clean Air Agency made the company add another two water trucks after complaints.

“My commitment to you and to everybody else here is that we are going to watch this very closely,” supervising inspector Mario Pedroza said.

State environmental officials will look at two different standards for cleaning the site. There’s a lower cleanup level required for areas put to future industrial use. A higher “unrestricted” level is necessary for other uses, including office space or public parks.

Any contaminated material that exceeds industrial cleanup levels must be hauled off site, Rogowski said.

“Industrial cleanup levels also must be protective of groundwater and protective of Puget Sound,” Rogowski said.

The City Council in January opted to zone large portions of the site for water-dependent industrial development, in hopes of attracting blue-collar jobs.

While they expected the shoreline to attract marine-related industry, they added flexibility away from the shore for office parks, open space and other development.

Councilwoman Brenda Stonecipher was the only vote against that plan, favoring instead zoning that would aim to attract more white-collar jobs.

Under either plan, Stonecipher believed that the cleanup would bring the old mill site up to unrestricted levels, so anything, in theory, could be built there. The site has not been sold, and, according to assessor’s records, is roughly valued at more than $30 million.

On Wednesday, Stonecipher worried the state would equivocate about holding Kimberly-Clark to that standard.

“From my perspective, I always thought it would be cleaned up to an unrestricted standard,” she said.

Stonecipher and Councilman Paul Roberts wondered if the requirements could be manipulated to save money. Kimberly-Clark, they reasoned, could exclusively market the property to industrial buyers requiring less cleanup.

That shouldn’t happen because cleanup is the state’s decision to make, according to a past state Department of Ecology director who has been retained by the city.

“Ecology will ultimately decide what the cleanup standard is,” Olympia attorney Jay Manning said. “Not Kimberly-Clark, not the potential buyer.”

For such a big, complicated site, the work could take three years or longer, Manning added. The solution may involve capping contaminated areas with soil or concrete.

The goal is to prevent people from coming in contact with pollutants, not necessarily removing every problematic substance. “Excavating every molecule just isn’t an option,” he said.

Rogowski said his agency takes the cleanup seriously, but the amount of arsenic in the mill debris is small compared to what Everett’s Asarco smelter left behind.

The threshold for arsenic, at both industrial and unrestricted levels, is 20 parts per million. Arsenic samples at the Kimberly-Clark site measure 20 to 40 parts per million, Rogowski said.

By comparison, the highest level found in a public place near the Asarco smelter was 314 parts per million in Legion Park, officials reported earlier. The highest level found in Wiggums Hollow was 210 parts per million.

Arsenic was the only contaminant found in a majority of the Kimberly-Clark debris samples, Rogowski said. Others, which are less widespread, include lead, cadmium and PCBs.

“Cleaning the site’s our responsibility, so we’ll do that,” Kimberly-Clark spokesman Bob Brand said. “We’re trying to be careful and to make sure the site can be used for its intended purpose.”

The decision to spread crushed concrete and other construction debris at the site eliminates the need for hauling away 12,000 truckloads of fill, and replacing it with an equal amount of material from off site, Brand said.

Depending on what samples show, the company may eventually be required to haul away some of the fill.

The Port of Everett has considered buying the land and continues to study the idea, port spokeswoman Lisa Lefeber said.

Nondisclosure agreements prevent Kimberly-Clark or the commercial real estate firm it hired from identifying potential buyers. Brand said there are several prospective suitors looking at the property for industrial uses.

Noah Haglund: 425-339-3465; nhaglund@heraldnet.com.