Welsbach/General Gas Mantle Superfund Site

History & Location

Welsbach/GGM in Gloucester City and Camden, New Jersey, used radioactive thorium to manufacture gas lamp mantles from the late 1800s to 1941. Thorium tailings were used to fill low-lying areas and provided sub-base and common fill for construction throughout the towns. Welsbach/GGM consists of multiple commercial and residential properties impacted with radiological contamination. Primary contaminants of concern at Welsbach included Ra226, Ra228, Th230, and Th232. Sevenson met radiation cleanup standard of 5 pCi/g above background on all properties in the scope and restored sites to pre-existing conditions.

Significant Project Features

• Work performed under the direction of the U.S. Army Corps of Engineers, Philadelphia District
• Performing highly complex excavation operations involving radiologically contaminated materials from 47 residential and 16 commercial properties
• Excavation, characterization, segregation, and disposal of 327,000 tons of radiologically contaminated soil and 61,000 tons of other contaminated media
• Designing, constructing, operating, and maintaining Waste Water Treatment Plants that effectively treated 42M gallons of contact and groundwater
• Successfully coordinating Transportation & Disposal (T&D) operations to safely convey 388,000 tons of radiological waste and other material to a USACE-approved landfill facility
• Completing all contracts and task orders on schedule and within budget
• Achieving over 1.2M safe workhours without a lost-time incident

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