Hanford was an old nuclear plant and one of the only - if NOT the only plant - that didn’t have a containment building around their reactor in it’s early years. The site was a disaster for years... IMHO...
The current commercial operational reactor is outputting isotopes right into an east wind; see the charts. Yakima is, ironically, in the plume shadow.
The Columbia Generating Station (former WPPSS site) is also on the Hanford 'site'.
It's amazing to me that all this data & research spans 40+ years and they're still reticent to give any credence at all to what, for some doctors & scientists, is already well-established.