Doe Run Co. Herculaneum Smelter

The Doe Run Co. owns approximately 300 acres along the west bank of the Mississippi River, including more than 6,400 feet of riverfront. When the lead smelter was in operation, lead concentrate from Doe Run's mining and milling facilities throughout southeast Missouri was transported to the Herculaneum smelter for smelting and refining. Because lead ore is often not pure lead, fluxing agents, such as limestone, are used in the smelting process. The fluxing agents react with the impurities and carry them off as slag. The slag was disposed of on-site, in two separate slag storage areas. 

The property includes several areas of interest, as shown in the map.

• Former Plant Parcel (smelter site) - 40 acres located west of the Union Pacific mainline railroad track. Owner: Doe Run.
• Port Parcel - 17 acers located between the smelter parcel and the Mississippi riverbank. Owner: Jefferson County Port Authority.
• South Slag Storage Area - Permitted slag landfill located south of the smelter. Owner: Doe Run.
• Voluntary Property Purchase Area - Former residential neighborhood west of the smelter parcel. Owner: Doe Run, with several privately owned residences remaining.

Closure

In 2013, sintering and blast furnace operations stopped at the site, with decontamination beginning in 2015. Decontamination activities progressed building by building, by removing and managing materials for recycling or, as necessary, off-site disposal. To the extent practicable, work was performed inside existing buildings to minimize dust and control associated emissions through operating the bag houses. Dismantling began in 2017 and was completed in 2018. 

Refinery operations stopped at the site in August 2021. Decontamination and demolition of the refinery and remaining process areas was completed in 2022. The perimeter dust monitoring system used during operation of the smelter remains in operation to monitor operations at the site.

Site Investigation

Site investigations have been conducted by Doe Run and their contractors under plans approved by EPA and the department. Between 2013 and 2017, potential sources of contamination were identified. Metals were in the underlying soil at levels significantly above state and federal standards for residential or non-residential use. Contamination on the smelter parcel was generally limited to the upper four feet, except for the north end of the site (Old Slag Storage Area). A deposit of pre-WWII shell slag, up to 40 feet thick, prevented drilling to verify the depth. Based on the slag sample analysis, the deposit was assumed to contain significant amounts of residual lead and other metals.

Groundwater concentrations of lead at the site exceeded federal drinking water standards. The contamination plume appeared to be confined to the site and was not affecting the Mississippi River or local public water supplies. Groundwater monitoring is ongoing.

The 2011 Multi-media Consent Decree requires Doe Run to remediate, or clean up, the Herculaneum facility to risk-based cleanup levels appropriate for the designated future use of the property, after the smelter is shut down. Past cleanup activities focused on off-site property, including replacing yard soil, residential home buyouts and a third party redeveloping the adjacent riverfront property as a port. The smelter parcel is the main focus of current remediation activities at the site. 

While remediation plans were being developed, Doe Run proposed transferring the large deposit of shell slag at the north end of the site (Old Slag Storage Area) to the South Slag Storage Area. The shell slag contained potentially recoverable levels of zinc, copper and other trace metals. The South Slag Storage Area already contained a large volume of modern sinter slag. It was also a more secure repository, where the slag is capped with soil to prevent release to the surrounding environment. The transfer plan was approved. Between 2022 and 2024, Doe Run transferred approximately 200,000 tons of slag to the South Slag Storage Area. 

Smelter Property Proposed Remediation Plan

Doe Run's proposed remediation of the smelter property includes regrading the contaminated soil, followed by securely capping it with clean soil, pavement or buildings. A cap is a horizontal physical barrier built over the contaminated soil to prevent humans and animals from being exposed to the wastes. Caps also prevent rainwater from soaking into the contaminated soil and leaching, or carrying, the wastes to the groundwater. The site would require grading to accommodate the proposed redevelopment into additional port facilities. 

The plan also includes an environmental covenant with attached management plan, signed by Doe Run and the department. Environmental covenants are legal instruments placed in the property chain-of-title, which place certain activity and use limitations on the property. The covenant would restrict the site property to non-residential use and prohibit drilling and use of shallow groundwater for drinking water. The covenant also would ensure the protective cap remains in place by requiring inspection and maintenance of the cap, with monitoring by the department's Long-Term Stewardship Program. The location and depth of contaminated soil would be clearly documented in the management plan.

The Doe Run Co. has entered into several enforceable agreements (consent decrees, orders and settlement agreements) with the department and EPA to address lead contamination in the region. The 2011 Multi-media Consent Decree between Doe Run and EPA governs cleanup of the smelter site. Initial investigations of the smelter property were conducted with EPA providing primary oversight, since EPA was the signatory to the consent decree. 

In 2022, the agencies finalized a Remedial Oversight Transfer Plan, which transfers primary oversight to the department. Under the transfer plan, the department’s Brownfields/ Voluntary Cleanup Program is responsible for day-to-day oversight and plan development. EPA retains final approval authority as signatory to the 2011 consent decree.

Listed below are the currently effective regulatory mechanism(s) and any supporting documents regarding this property that the department currently has available in electronic form. These include reports about investigations and other activities conducted since 2012. Due to the volume and age of the files, most of the older documents have not been digitized. You can review printed copies of complete files on the Doe Run Herculaneum site at the department’s Elm Street Conference Center in Jefferson City, Missouri. To review or obtain copies of the department’s files, please submit a Sunshine Law Request.

The department realizes some of the electronic files can be quite large, which may result in long download times for individuals with slow internet connections. If you have any problems accessing these documents, please contact the department’s Brownfields/ Voluntary Cleanup Program.

Documents