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HTDS Guide

The Hanford Thyroid Disease Study
HTDS Guide > Hanford History > About the Hanford Nuclear Site

HTDS Guide

Hanford History
Section Summary
About the Hanford Nuclear Site
Exposures to Radiation
Classified Information Released
Why the HTDS Was Conducted

About the Hanford Nuclear Site

The Hanford Nuclear Site occupies about 560 square miles in southeastern Washington State, adjacent to the towns of Pasco, Kennewick and Richland. The facility was the world's first large-scale nuclear production plant. It was constructed in the early 1940s as part of the Manhattan Project to produce plutonium for nuclear weapons.

Over the course of many years, large amounts of radioactive materials (radionuclides) were released into the atmosphere and the Columbia River as part of the plutonium production process.

The major radioactive releases occurred in the form of gases and particles into the air from 1944 through 1957. These releases occurred mainly because of increased production and lack of filter systems. Changes in the production process over the years greatly reduced releases into the air.

Many different kinds of radioactive materials were released. For many people living in the region, most of their dose was due to iodine-131 released into the air.

Hanford Nuclear Site and Surrounding Areas

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