Tacoma Smelter Plume — history & studies

In the mid-1990s, the Environmental Protection Agency (EPA) required Asarco to start cleanup work in the Ruston/North Tacoma Study Area under the Superfund program. Their work focused on the areas most affected by the former Asarco smelter.

The EPA study area in stretches from Lexington street and Park Avenue in the north east to the waterfront and south to 37th. It is divided into five zones. The former smelter was located in Ruston. — This is a map of the EPA Superfund study area. It also shows the sequence of our future work. We are currently working in Areas 1 and 2.

The former Asarco smelter site, also known as the Tacoma smelter, was one of the first Superfund sites in the nation. Under EPA's oversight, Asarco sampled soil at 3,570 properties in Ruston and North Tacoma and replaced soil at 2,436 of those properties. The EPA's work focused on the areas closest to the former smelter. Properties qualified for soil work when they had arsenic levels over 230 parts per million.

If you live in the study area (see map), it is very likely that your property was sampled by the EPA. To find soil sampling information for your yard, go to our public database.

Managing risk and addressing soil contamination

Today, we continue the work on yards that was started by the EPA over 20 years ago. We work area by area to replace soil containing high levels of lead and arsenic. In some cases, we go back to places that did not qualify under the EPA’s program to replace soil in those yards.

The Interim Action Plan is Ecology's plan to address contamination in the overall Tacoma Smelter Plume (over 1,000 square miles). In June 2012, after incorporating public comments, Ecology issued the final Interim Action Plan.

Asarco Tacoma Smelter Site: Final Interim Action Plan for the Tacoma Smelter Plume (2012)

The Final Program Design and Implementation plan is Ecology's plan to address contamination in the Yard Program Service area. This is the area closest to the former smelter. The main objective of the Yard Program is to reduce human health risk from arsenic and lead in soils. We meet this objective through soil sampling, soil replacement, and outreach.

Tacoma Smelter Plume Residential Yard Sampling and Cleanup Program: Final Program Design and Implementation Plan (2013)

In 2006, Ecology also started the Soil Safety Program to assess and sample soil at schools and licensed childcare facilities within the Tacoma Smelter Plume. In 2010, Ecology amended the design to include parks, camps, and public multi-family housing play areas.

Soil Safety Program Final Design Document (2006)
Addendum to the Soil Safety Program Design (2010)

Studying contamination

The start of cleanup raised interest in cleaning up arsenic and lead contamination beyond EPA’s cleanup area. Early studies from before 1987 looked at soil in yards, play fields, forests, and other areas. However, many of the studies had few samples and only covered small areas. In 1999, Ecology began working with local health departments on a series of studies to find the full extent of smelter contamination.

The first phase of studies consisted of “footprint” sampling. We wanted to find out how far contamination went and how high the levels were.

Footprint study findings

Ecology ended up with 4,175 samples from 851 locations. They show higher levels closer to the former smelter, but the levels vary greatly, even within a small area. The Tacoma Smelter Plume map is based largely on data from these studies.

Vashon-Maury Island – Undisturbed Area Study Report (2000)
Mainland King County Preliminary Study Report (2002)
Pierce County Footprint Study Report (2004)
Extended Footprint Study Report (2005)

The second phase of studies looked at places where children play, such as schools, childcares, and parks. These studies provided us with a better picture of contamination in places where children might be at risk.

Vashon-Maury Island Child-use Area Study Report (2001)
Mainland King County Child-use Area Study Report (2003)
Pierce County Child-use Area Study Report (2004)
Pierce County Child-use Metro Parks Study Report (2006)

These studies helped define the Tacoma smelter plume, linked Asarco to the contamination, and explored using ferns to clean up soils.

Sources of contamination

Ecology evaluated the possible source or sources of the contamination and compiled this information in the Credible Evidence Report below.

Trace Element Analyses (2003)
Credible Evidence Report (2004)

Fern Phytoremediation Study

Some plants readily take up arsenic and other heavy metals from the soil. The Chinese brake fern (Pteris vittata) can take up arsenic into its fronds at a very high rate. From 2005 to 2007, Ecology did a study to see if the Chinese brake fern could clean up Tacoma Smelter Plume contamination.

**Findings: Ferns are not a good cleanup tool for the Tacoma smelter plume;** see the reports below for why.

Fern Study “Final Report” Slideshow (2013)
Study Intro (2005)
Study Update (2005)

Contact information

Marian Abbett
Project Manager
Marian.Abbett@ecy.wa.gov
360-407-6255

Tacoma Smelter Plume — history & studies

Managing risk and addressing soil contamination

Studying contamination

Related links

Contact information