Looking at what is now Dune Peninsula park on the Tacoma waterfront, it's tough to imagine what the area looked like just a few decades ago.
For almost 100 years, a copper smelter operated along the waterfront.
Though the smelter was originally celebrated, it became widely criticized for the amount of pollution it generated. The facility released sulfur dioxide and contaminated dust into the air. Much of that dust settled in the soil throughout the area.
Additionally, slag - or byproducts from the metallurgy process - was dumped into Commencement Bay. It included lead, arsenic, copper, and other metals.
The facility operated from 1890 until 1986. In 1985, smelting operations ceased. In 1986, the facility closed permanently.
Also see | Dune Peninsula park opens July 6 in Tacoma
In 1987 and 1988, Asarco, the owner of the facility, removed many of the most contaminated buildings from the property. In 1993, the well-known smokestack was imploded.
The EPA also required Asarco to begin cleanup in the Ruston/North Tacoma study area, which stretched from North Lexington Street to the waterfront. In 1993, the EPA adopted a final cleanup plan for the Ruston/North Tacoma study area.
So where does the Dune Peninsula park come in?
The 26-acre peninsula the new park sits on is comprised entirely of the potentially toxic slag from the former smelter that was dumped into the bay.
Steps have been taken to protect the public.
A cap was installed over the entire peninsula to isolate the contamination in the slag from the soil for the park. The cap consists of multiple layers of geotextile liner, soil, and drainage material, according to EPA spokesperson Suzanne Skadowsk. The EPA provided Metro Parks with the design of the cap and oversaw the construction.
"Several feet of soil cover the cap to provide a protective barrier between the cap and the park," she told KING 5.
The shoreline itself was covered with a filter fabric and rock to prevent erosion of the toxic slag into the bay.
Following the multi-staged cleanup effort, the property was deemed safe for recreational use as a park, according to Skadowski.
The park opened July 6.