The effects on the population in the vicinity of Three Mile Island from radioactive releases measured during the accident, if any, will certainly be nonmeasurable and nondetectable. During the course of the accident, approximately 2.5 million curies of radioactive noble gases and 15 curies of radioiodines were released. These releases resulted in an average dose of 1.4 mrem to the approximately two million people in the site area.

  This average dose is less than 1 % of the annual dose from both natural background radiation and medical practice. The 1.4-mrem dose may also be compared to differences in annual doses in background radiation from living in a brick versus a frame house, an additional 14 mrem/yr; or living in the high altitude of Denver rather than in Harrisburg, an additional 80 mrem/yr.

  The effect of this total dose, averaged over the population in the site area, will be to produce between none and one additional fatal cancer, and between none and one and a half total (fatal and nonfatal) cancers, over the lifetime of the population. In comparison, approximately a half million cancers are expected to develop from all other sources during this same lifetime.

I don't know if the previous commenter was saying all two million people in the area are black, but they do seem to be considered in this Three Mile Island Report volume 1[1], page 153.

[1] https://www.osti.gov/servlets/purl/5395798 (PDF)

If you believe this, I have some land on the Big Island to sell you.

Note the weasel wording "averaged over". Nobody had "averaged over" exposure. Instead, the people who were most exposed were most exposed.

It would be good to see the data that supports, or at least clarifies, what you're saying.