The ASARCO Smelter and Tacoma Real Estate: What Buyers Need to Know About the Soil

For almost 100 years, the ASARCO copper smelter operated in Ruston and North Tacoma before closing in 1986. During those decades, air pollution from the smelter deposited arsenic and lead across more than 1,000 square miles of the Puget Sound basin, an area known today as the Tacoma Smelter Plume.

It is one of the first Superfund sites in the nation, and the contamination it left behind still matters to anyone buying a home in the affected area. Here is what buyers need to know.

What the Contamination Is

The smelter's emissions spread arsenic and lead across a vast swath of central Puget Sound, carried downwind from the plant. The heaviest contamination is concentrated in Tacoma and north Pierce County near the original site, with levels gradually decreasing as you move further from the smelter.

Soil is the key concern. Arsenic and lead sit in the top layers of soil, which matters for anyone who gardens, has young children playing outside, or will be digging or developing the property.

Important context: for most properties in the plume, the contamination poses only a very small, long-term health risk. The highest-risk scenarios involve direct contact with contaminated soil, especially for children, and growing food in heavily contaminated soil. This is a manageable issue, but it is one buyers should understand before they close.

The Good News: Decades of Cleanup Work

There has been extensive cleanup across the region.

Under EPA oversight, soil was sampled at roughly 3,570 properties in Ruston and North Tacoma, and replaced at about 2,436 of those homes. The Washington State Department of Ecology runs the Soil Safety Program and the Yard Program, which offer free soil sampling and, in eligible areas, soil replacement for residential properties with the highest contamination. Ecology maintains an interactive map, called the Dirt Alert map, that lets anyone look up an address and see whether a property has been tested and what the results were.

So for many homes in the plume, contamination has already been addressed. And for those that have not, there are available resources, often free, to test and remediate.

What Buyers Should Do

If you are looking at a home in the plume area, add these steps to your due diligence:

• Check the Dirt Alert map. This is your first and easiest step. Search the address to see if the soil has been sampled and what the results showed.
• Look up whether the property is in the plume. Ecology's interactive map shows whether a property falls within the affected area.
• Request soil testing. If a property is in the plume and has not been tested, Washington State Department of Ecology offers free educational sampling for many residential properties, especially useful for yards where children play, areas with exposed soil, and gardens.
• Ask about the seller's disclosure. Washington State real estate law requires sellers to disclose known contamination. Ask directly whether the property has been tested, the results, and any records of cleanup work.
• Talk to a specialist before major projects. If you plan to dig, build, or landscape extensively, understand the contamination level first. Developers can work with Ecology's Voluntary Cleanup Program, which has supported many projects in the plume.

A balanced perspective matters here. Arsenic and lead in soil is a real consideration, but for the vast majority of properties it is a small, long-term risk that can be managed with simple healthy actions, keeping soil covered, washing hands and produce, and testing before gardening or building. This does not make the area unlivable. It makes it an area where informed buyers do their homework.

What This Means for Value

Does contamination affect property value? It can, in one of two ways. On the one hand, a fully tested and remediated property is a strong selling point. The environmental work is done, documented, and buyers can have confidence. On the other hand, an untested property in the plume may carry uncertainty, and some buyers will ask for a price adjustment or soil testing before committing.

The most favorable scenario is a home that has already been sampled and cleaned up, with documentation in hand. That removes the uncertainty and makes the transaction smoother.

The Bottom Line

The ASARCO smelter left a real legacy, and the Tacoma Smelter Plume is a fact of life for buyers in Ruston, North Tacoma, and parts of the greater Puget Sound area. But it is far from a deal-breaker. Decades of cleanup, free testing resources, and well-documented remediation programs mean this is a manageable, and often already-resolved, issue.

If you are considering a home in the affected area, do your due diligence: check the Dirt Alert map, request soil testing where it makes sense, review disclosures, and ask the right questions. A knowledgeable agent and the right resources can give you confidence in your decision.

If you are looking to buy in Tacoma, Ruston, or anywhere across the Puget Sound, let's talk. I help buyers navigate these considerations so they can move forward with clarity.