Mound Laboratory, Miamisburg Ohio

MoundMound is a DOE facility for 1947 to the present so workers are eligible to file both Part B and Part E claims.

Mound has three Special Exposure Cohorts which cover specific workers with specific cancers and at least 250 days of employment for January 1, 1952-December 31, 1967.

In 1943, the Manhattan Engineer District began the Dayton Project to investigate the chemistry and metallurgy of polonium. From 1943 to 1948, this work was performed at several locations throughout Dayton, Ohio, all of which were too small to perform the mission. The Mound Plant was constructed in 1947 in Miamisburg, Ohio, to replace these earlier work locations. This plant was first occupied in May 1948 and became operational in February 1949.

The facilities’ first mission was to manufacture polonium-beryllium initiators for atomic weapons. As part of this process, the site extracted polonium-210 from irradiated bismuth slugs and machined beryllium parts. Mound stopped producing initiators after the Pinellas Plant in Florida began producing accelerator-type neutron generators in 1957. In 1954, Mound began developing and producing weapons components containing tritium, and in 1969, the plant began recovering and purifying tritium from dismantled nuclear weapons. During the 1950s and 1960s the Mound Plant also developed and produced a variety of nonnuclear weapons components including detonators, cable assemblies, firing sets, ferroelectric transducers, and explosive timers. In 1995, Mound discontinued weapons component production.

The non-weapons work performed at the Mound Plant included the development and manufacture of radioisotope thermal generators; radioactive waste decontamination research; investigation of the properties of uranium, protactinium-231, and plutonium-239; and the separation of stable isotopes and noble gases.

Throughout the course of its operations, the potential for beryllium exposure existed at this site, due to beryllium use, residual contamination, and decontamination activities.

Construction of Mound Laboratory began in 1946, and the site became operational in 1949. Mound, the nations first post-war U.S. Atomic Energy Commission site to be constructed, was established to consolidate and continue the work conducted at the Dayton Units for the Manhattan Project. Mound was located on 306 acres in Miamisburg, Ohio and at its peak had 116 buildings.

Much of the work at the Mound during the Cold War involved production of the polonium-beryllium initiators used in early atomic weapons and the manufacture of and research related to radionuclides. In the 1950s, the facility began to manufacture a variety of nuclear weapons parts, including cable assemblies, explosive detonators, and the electronic firing sets that activated them. Work at the Mound Plant evolved and grew to include stable isotope separation, fossil fuels research, tritium recovery for reuse in weapons, development of radioisotopic thermoelectric generators used to provide electrical power for space exploration, and other non-nuclear research and development activities. The Mound Plant ceased non-weapons work in 1972 and stopped production of weapons components in 1995.

Alternative Names

  • Mound Plant
  • Mound Facility
  • The Mound Miamisburg Closure Project
  • Miamisburg Environmental Management Project (MEMP)
  • Unit IV


Mound’s CERCLA Reading Room has moved to Fernald . Online access to CERCLA documents is available as well.


DOE Legacy Management has a webpage on Mound.

DOE Contractors

  • S.M. Stoller Corporation (2006-present)
  • Accelerated Remediation Company (2006-2010)
  • CH2M Hill (2003-2006); BWX Technologies (1997-2002)
  • EG&G Mound Applied Technologies (1988-1997)
  • Monsanto Chemical Company (1947-1988)


DOL lists Part B and Part E statistics for Mound as well as maintaining a Mound Site Exposure Matrix.



Ohio EPA also has a Mound webpage.



NIOSH provides dose reconstruction statistics for Mound. NIOSH has Technical Basis Documents for Mound. Mound also has two Special Exposure Cohorts. The first is for workers from October 1, 1949 through February 28, 1959. The second one is for workers who had at least 1 tritium bioassay from March 1, 1959 through March 5, 1980. There is a problem with this SEC that NIOSH and DOL are trying to resolve. See the next section for information on that.



Mound Videos

Mound Documents

Tiger Team Assessment of the Mound Plant Miamisburg, Ohio–December 1989


SM-Building Incident and Accident Reports


Mound Laboratory Notebook Index for 1944-2006

This index is of handwritten Mound laboratory notebooks. If you find something of interest in the index you can do a Freedom of Information Act (FOIA) request on the specific notebook you want to see.


Meyer Histories of Internal and External Dosimetry


Mound 1948

Mound 1949

Other Mound Documents

MLM-CF-65-12-232 Plutonium Receipts for 1956-1964