But krypton gas is 3x as dense as air. Xenon is 5x. They don't mix eagerly with air, but run downhill more like a (fluffy) liquid. Riding above the water, they run freely over low obstacles to water flow, and spread out far beyond the water's edge. These gases would have run down the Susquehanna River and spread out in the bottom lands along it.

The paper cited in [1] is extremely guarded in its estimates of exposure to Kr radioisotopes, particularly concerning the more active ones like Kr87, 88, and 79. They note that helicopter sampling would produce unreliable measures, and the first measurements of any kind did not occur until 2 days after the incident, when the most active would have largely decayed, and (anyway) run downstream.

The peer-reviewed "A reevaluation of cancer incidence near ..." by Wing et al. ( https://ehp.niehs.nih.gov/doi/pdf/10.1289/ehp9710552 ) concludes that increased incidence of cancer around the plant is not consistent with published estimates of releases.

Evacuation was not suggested until two days after the event, and few did, as there were numerous assurances that it was safely contained.

Disingenuous disavowals of harm no not increase credibility.