Was that the only issue over the years at this site though?

Others have cited four 'incidents' reported (I have no idea what these were), various experiments and tests, and I imagine there's the implication of a legacy of less than rigorous material handling and storage being possible.

From the wikipedia page: > At least four of the ten nuclear reactors had accidents during their operation.

> The reactors located on the grounds of SSFL were considered experimental, and therefore had no containment structures.

Given all that I'd say the possibilities are wide open.

> Got any publications describing this concern in more detail?

Your best bet might be to drop Alex Wellerstein a line and ask if he knows of (or knows anyone who knows of) what documents the DOE | NASA have released into the public domain and whether there are whispers of further releases in the wind.

I tend to track things of this nature not in central north america.

[1] https://en.wikipedia.org/wiki/Santa_Susana_Field_Laboratory

[2] https://alexwellerstein.com/writing/books/restricted-data/

Measurable radioactive dose is easy to measure, so of course it is what you would like us to pay attention to. But radionuclides invading tissue is what causes cancers. Those risks are harder to measure. Which radionuclides? What grain size? A nanogram of the wrong stuff in the wrong place is all it takes.

Not to mention the chemical toxicity of many of them is non trivial.