Paducah workers during the Cold War may have been exposed to five airborne hazards.
By Joe Walker firstname.lastname@example.org
Two new Department of Energy reports say workers potentially were exposed to airborne hazards while recovering metals, notably gold and silver, at the Paducah Gaseous Diffusion plant during the Cold War years.
Five materials — the metals beryllium, cobalt, lead and tantalum, and the radionuclide tritium — may have caused health and environmental hazards, according to the reports, issued Thursday. The materials were used mainly in processing weapons components as part of plant work for outside firms and government agencies.
The work, which took place from 1952 to 1986, included recovering precious metals from damaged and retired nuclear weapons; fabrication of moon landing parts for the National Aeronautics and Space Administration; making research nuclear reactor components; and assembling electronics and parts for missile systems. Other work involved the recovery and recycling of metal from weapons casing and electronics, and the destruction of classified parts for security reasons.
The report says DOE's Office of Environment, Safety and Health, which oversees an ongoing worker health study, should review the information to see if more action is needed. DOE officials said additional steps could include asking that new worker compensation laws — which cover beryllium and radiation sickness — be expanded for lead and other exposures.
--The former torching, machining and melting of lead, and the machining and crushing of beryllium and beryllium-copper alloy, should be evaluated further.
--More review of burial practices is needed because of the plant's burial of neutron generators containing tritium, beryllium-contaminated materials, and the volume of beryllium and other materials from the weapons program. That data will provide better information about buried materials and containers before excavation. Don Seaborg, DOE's Paducah site manager, said there are no plans to dig in the classified burial yard where most of the materials are stored. The site is scheduled for cleanup in 2009.
--Work-for-others program records should be centralized, indexed and cross-checked with other facilities to validate and quantify hazards identified.
--Information in the reports should be provided to regulators and interested citizens to make them aware of past work at the plant. Dale Jackson, director of uranium management for DOE's Oak Ridge, Tenn., operations, including Paducah, said sampling shows current workers are not at risk because of the Cold War work.
Highlights of the reports:
--Metals processed were gold, silver, steel, nickel, aluminum, copper, monel (a copper-nickel alloy) and cobalt. A smelter and two sweat furnaces were used, and an induction furnace was added in 1976 to process metals with higher melting points. The smelter was used to destroy the classified aspect of parts used to enrich uranium at the plant, and to recover nickel from production parts removed from enrichment plants at Paducah, Ohio and Tennessee. As late as 1986, some radioactive materials were shipped to the Paducah plant for smelter processing. Radioactively contaminated materials from the plant were processed with the same equipment.
--Many of the materials formerly handled by Paducah plant workers are known today to be hazardous and require protection. In the early days of the plant, those hazards were not as well-known. When smelting started, equipment was not generally used to protect workers from vapors and particulates during furnace operation and slag cleaning. Later, as hazards were better understood, health and safety controls were specified.
--Available records show 2,800 to 5,300 pounds of gold were recovered and shipped from the plant from 1964 to 1985 in contaminated areas of a cleaning building and a smelter.
"The worst-case use of gold would have been through pharmaceutical injection in arthritic patients. If this material were used for this purpose, it would have resulted in an exposure of about 30 millirem, or 10 percent of annual natural background (radiation). But this exposure scenario is extremely unlikely." DOE officials said in interviews that there is no evidence such injections really took place.
--About 7,650 pounds of silver were reclaimed by reprocessing classified X-ray film from 1966 to 1974. The film was incinerated and the ash smelted into silver bars in a foundry. Cross-contamination could have occurred during processing, but there is no evidence of the potential for dangerous levels of contamination.
--Lead was recycled with weapons parts. The only records available said 258,990 pounds of shredded lead were produced and sold. The lead had slight potential for cross-contamination during processing. In the mid-’60s through late ’70s, Paducah was asked to fabricate X-ray lead shield doors poured in two sections, each with 26,000 pounds of lead. Also, lead was scavenged from abandoned Kentucky Ordnance Works facilities near the plant by using torches to cut and extract lead.
--Much of the outside work was done in the plant machine shop, a state-of-the-art facility during the Cold War. Workers were at greatest risk in the melting and machining of lead, and the machining of beryllium, and beryllium-copper compounds. Beryllium hazards were partly recognized, but records and workers' memory show no clear evidence that recommended protective measures like controlled ventilation and respirators were used.
--About 17 million pounds of "clean" nickel, recovered by smelting into ingots, were sold. Samples showed low levels of contamination of technetium-99 and plutonium — radioactive substances contained in uranium recycled from nuclear fuel — but "these levels would have had no public health consequence." Nearly 20 million pounds of contaminated nickel were cast and remain in a plant scrap yard.
--Roughly 4.5 million pounds of aluminum were smelted into ingots from 1970 to 1986. Records before 1984 could not be found. Samples showed low levels of plutonium and two other radionuclides. Although the aluminum was not a general public health threat, "the potential to exceed annual radiation-protection standards for the public might possibly have existed at foundries (outside the plant) where this aluminum was remelted."
--Scrap steel was segregated into contaminated and clean areas, but no documents were found, and clean areas sometimes were contaminated. Excess clean steel was sold, and contaminated steel may have been sold. Steel known to be contaminated was routinely placed in a scrap yard and not sold. About 26.7 million pounds of contaminated steel scrap were generated. Smelting was cut short because of process problems, and the ingots remain with contaminated scrap.