The IAEA's 1988 primary report states that 249 of ~112,000 people monitored were contaminated in the Goiânia accident

radiological-medicineradionuclideshistorygoiania-accidentiaeacesium-137primary-verification

The IAEA's own 1988 account of the Goiânia accident, The Radiological Accident in Goiânia (STI/PUB/815, ISBN 92-0-129088-8) — a formal published report assembled jointly with Brazil's National Nuclear Energy Commission (CNEN) from a review meeting of an international panel of specialists — gives the screening and contamination totals directly, distinguishing the much larger number of people checked from the smaller number found to be actually contaminated:

"In total, some 112 000 persons were monitored, of whom 249 were contaminated either internally or externally."

This is the primary source the commonly cited "~249 contaminated" figure traces back to; it is not a later approximation drifting through secondary retellings. The number clears the sourcing floor for a quantitative claim (Tier 1–2 required), and resolves the [unverified-quant — needs primary] flag carried since 2026-07-11, when only a Tier-4 aggregator was reachable.

It sits alongside two sibling findings drawn from the same document: the death count and dosimetry and the accident's causal mechanism. All three rest on this one institutional document — formal and ISBN-carrying, not an unrefereed preprint, but still a single voice; independent corroboration (Brazilian Ministry of Health epidemiology, WHO) was sought this session and not found.