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The View-Master factory supply well in Beaverton, Oregon, was evaluated for public health effects by the Oregon Department of Human Services (ODHS) under a cooperative agreement with the Agency for Toxic Substances and Disease Registry (ATSDR). Workers there were potentially exposed to the industrial solvent trichloroethylene (TCE), classified by the International Agency for Research on Cancer (IARC) as a probable human carcinogen. At the factory, which closed in 2001, it had been estimated by ODHS that up to 25,000 workers may have been exposed to TCE via the factory's drinking water, which was drawn from a well on-site. However, further investigation showed that the actual number of employees who can be identified from employment records for the site is approximately half that number. In addition, the number of employees identified as having worked at the site for more than five years is likely to be less than 1,000. The site is now considered safe. ==History== The View-Master, a device for viewing 3-D images (also known as stereo images) on a paper disk, was invented in 1939 by William Gruber, a Portland, Oregon, photographer. A business arrangement was made, and the devices came to be manufactured by Sawyer's, Inc. In 1951, Sawyer's opened a factory in Progress, Oregon (now part of Beaverton), to manufacture the devices. The devices were manufactured at the factory in Beaverton until 2001, when production was shifted elsewhere and portions of the factory sold.〔 In 1998, a prospective site developer hired an environmental engineering firm to perform an environmental assessment of the site. This assessment discovered volatile organic compounds well above the levels specified by the United States Environmental Protection Agency (U.S. EPA). This included levels of TCE which were over 300 times the federal drinking water standard. The various concerns who owned the View-Master franchise in the 1950s through the 1970s (Sawyer's and GAF), acknowledged using TCE to clean and de-grease parts and equipment, and disposed of the chemical on-site.〔 This disposal was legal at the time. IARC has classified TCE as “probably carcinogenic to humans”.〔 The U.S. EPA is in the process of evaluating the carcinogenic and non-carcinogenic human health risks from exposure to TCE.〔("EPA External Review Draft: Toxicological Review of Trichloroethylene. October 2009." )〕 Certain uses of TCE were banned in 1977 in the United States. However, TCE was still used in household products such as spot removers and typewriter correction fluid well into the 1990s.〔("ATSDR. Toxicological Profile for Trichloroethylene. Agency for Toxic Substances and Disease Registry. September 1997." )〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「View-Master factory supply well」の詳細全文を読む スポンサード リンク
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