The Mexico City Radiation Accident of 1962

Cobalt-60 Capsule

A ten-year-old boy brought home an industrial radiography source that was not properly shielded, causing a radiation incident in Mexico City between March and August 1962. The 5-Ci cobalt-60 capsule caused significant radiation overdoses in five people, four of whom passed away.

Concerning the provenance of the source, reports vary: “was left to the family to keep and watch without any of the members of the family knowing exactly what the container was” means that it was either discovered in a field, found in a dump, or already in the yard of the house when the affected family moved in.

The boy carried the capsule in his pocket for a few days before his mother put it in the kitchen cabinet of their house. The boy passed away on April 29 after receiving the source on March 21. His two-year-old sister passed away on August 18, his pregnant mother on July 10, and his grandmother passed away on October 15 of that same year. The boy’s father was also exposed to a significant amount of radiation; But he made it through, probably because he worked outside the home and was less exposed.

What Happened?

  • Boy discovered an unshielded industrial radiation source.
  • Boy carried the source in his pocket for days.
  • Later, boy placed it in the kitchen cabinet at his residence.

What was the radiography source?

  • 5-Ci cobalt-60
  • Radioactive isotope of Cobalt
  • Beta & Gamma Ray emitter
  • Half-Life: About 5 yrs

Detailed Aftermath

The official report does a painstaking job at estimating each family member’s total exposure based on different factors like how much time they spent in each area of the house and how contaminated these areas were. The mother had the highest dose of all household members except for the son (whose dose was hard to calculate, because the researchers couldn’t find out how long he kept the capsule in his pocket). In addition to the factors we already speculated about (all of which turned out to be true), the mother spent long periods in bed once the radiation symptoms set in. Her bed was in a fairly irradiated area of the house, so this led to moderate (in comparison to the kitchen) but constant exposure.

This also got grandma killed. Grandma moved into the house after the son fell ill and mom showed the first symptoms. She took over more and more household chores from mom, spending more time in the kitchen of doom.