State officials expect to complete a cleanup project at Dockton Park this week, where they’re removing thousands of cubic yards of contaminated soil from an area next to the popular playground.

Soil samples showed that a swath behind the playground — about a quarter of an acre in size — had arsenic and lead levels higher than what the state considers safe. Samples showed arsenic levels at 24 parts per million in one spot and 63 ppm in another, said Hannah Aoyagi, an outreach and education specialist at the state Department of Ecology. State standards consider 20 ppm a safe level.

The contamination came from the former Asarco copper smelter in Ruston, which produced an arsenic- and lead-laced plume 1,000 acres in size. The corporation filed for bankruptcy in 2005; the state, as part of the bankruptcy proceedings, was awarded $188 million in settlement funds.

For years, the state has had a soil safety program in place to address contamination, focusing its efforts on schools and child care centers, Aoyagi said. The settlement funds gave the Ecology Department the money to expand the program, addressing parks, camps and multi-family housing in its cleanup program.

The $115,000 project at Dockton is one of seven slated for this fall, she said.

“It’s an area where a lot of kids regularly spend time, so we felt it was important,” she said.