Superfund Information Systems: Site Profile

Superfund Site:

EAST HELENA SITE
EAST HELENA, MT

Cleanup Activities

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Background

The East Helena site is located in East Helena, in Lewis and Clark County, Montana. The site includes a lead smelter that operated from 1888 until 2001, the town of East Helena, several residential subdivisions and surrounding rural agricultural lands. For more than 100 years, lead and zinc smelting operations deposited heavy metals, arsenic and other hazardous chemicals into the soil, surface water and groundwater of the Helena Valley. The sources of this contamination included the smelter stack, fugitive emissions from plant operations, process ponds and direct surface water discharges. Historically, the mode of transport for the contaminants was air and surface water. Cleanup at the site is ongoing.

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What Has Been Done to Clean Up the Site?

At the former smelter site, all structures of the former smelter have been demolished, and contaminated soils and materials have been consolidated and covered with a 62-acre protective layer to prevent rain and snow water from seeping through and contaminating groundwater.

Contaminated water from onsite water bodies has been drained, reducing groundwater flowing through contaminated site soils. Prickly Pear Creek has been restored and 50 acres of wetlands created. Portions of the slag pile have been reshaped to prevent contaminants falling into Prickly Pear Creek.

In East Helena, a local soils ordinance (PDF) (14 pp, 589 K, About PDF) was adopted in 2012 to govern soil displacement and disposal. Contaminated topsoil has been removed and replaced from 786 residential yards, 50 commercial properties, 373 unpaved road aprons, 75 unpaved alleys, 14 unpaved roadways, 11 parks/public areas, 4 school playgrounds or church properties, 141 flood channel sections, 80 flood ditch sections, 4 parking lots and 38 vacant lots. In 2013, the Department of Natural Resources and Conservation adopted the East Valley Controlled Groundwater Area Exit, which manages new wells and prevents exposure to arsenic and selenium contaminated groundwater.

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What Is the Current Site Status?

One of the last remaining residential yards eligible for cleanup in East Helena has been completed. Remediation of the former smelting site is ongoing with construction progressing on covering consolidated contaminated soils and materials to protect groundwater. Prickly Pear Creek now flows through a new, 1½-mile-long channel and floodplain that was reconstructed as part of the effort to address contamination in soils and groundwater at the former smelting site.

In 2016, EPA completed the fourth five-year review of remedial actions performed at the East Helena Superfund site. Five-year reviews are conducted to determine how the remedy is working and if the remedy remains protective of human health and the environment.

EPA oversees and approves activities related to the cleanup of the former Asarco smelter site in East Helena Montana. EPA continues to work closely with private homeowners, East Helena City and Lewis and Clark and Jefferson County officials to ensure cleanup efforts continue to protect human health and the environment.

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