The Radiological Incident in Ciudad Juárez

One of the worst radiation accident in North America took place in the city of Ciudad Juárez, Mexico, in 1984. Although the incident is relatively unknown, it has been called “a hundred times more intense” than the 1979 Three Mile Island accident.

It began in 1983 when Vicente Sotelo, a technician working at a city hospital, went into a general warehouse to pick up some supplies. The hospital rented space at the warehouse and used it to keep unused equipment and other stuff. Among the things Sotelo picked up that day was a cylinder containing highly radioactive cobalt-60 in the form of small pellets. The cylinder was part of a radiotherapy unit the hospital had purchased six years earlier but it wasn’t put to use. The hospital failed to notify the regulatory authority about the purchase which was required by law. It also did not monitor the status of the unit. Sotelo, unaware of the nature of the metal cylinder, loaded the radiotherapy unit into a pick-up truck and drove to a scrapyard intending to sell it. However, before arriving at the scrapyard, he attempted to pick apart the cylinder causing the radioactive pellets to spill onto the bed of the vehicle.

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Upon his return from the junkyard, the truck suffered mechanical failure and remained parked near his home for 40 days. After this time, the truck was moved to a different street where it stayed parked for a further ten days.

Meanwhile, at the junkyard, when the cranes moved the cylinder together with other pieces of metal, the cobalt-60 pellets were spread all over the scrapyard mixing in with other metals. This radioactive scrap was sent to two foundries where they were melted and rebars for construction and metal table frames were manufactured out of the contaminated material. By January 1984, less than a month after the incident, these materials were already exported to the United States and the interior of Mexico.

On January 16, a truck loaded with rebar accidentally passed too close to the Los Alamos National Laboratory in New Mexico, causing the radiation detector at the laboratory to record a sharp spike. Upon investigating, authorities realized the source of the radiation was the truck’s cargo. Mexico's National Commission on Nuclear Safety and Safeguards (CNSNS) was notified, which confirmed that a radioactive spill had occurred and ordered the foundries to suspend the distribution of manufactured rebar. The junkyard was also shut down.

When CNSNS scanned Sotelo’s abandoned truck it was found emitting deadly radiation levels of up to a thousand roentgens per hour. The truck had remained parked close to two homes, and children regularly played upon it. Further investigation revealed that in addition to the junkyard, and the two foundries, three other companies had received contaminated material. Out of this material, some 30,000 table bases and 6,600 tons of rebar was made.

CNSNS managed to recover 2,360 tons of unused rebar. The rest was already used in construction. Authorities identified 17,000 buildings that were built with contaminated rebar, and determined that some 800 structures would need to be demolished due to unacceptable levels of radiation. CNSNS also managed to recover all of the 30,000 contaminated table bases, in addition to about 90 percent of the thousand tons of contaminated rebar that had been exported to the United States. About a thousand ton of contaminated rebar still remained unaccounted for.

The accident proved to be costly to Mexico. However, the individuals who were most directly exposed to the radioactive cobalt may have suffered the greatest toll. According to some estimate, about 4,000 people got exposed with about 80 people receiving doses greater than 25 rems. Of these, five people received a dose between 300 and 700 rems over a period of two months. Chronic doses above 20 rem increase the risk of cancer, while acute doses of 500 rem kill half of those affected without medical treatment. Fortunately, there were no deaths from this incident.

Sotelo was dismissed from his job; the clinic claimed that he was not authorized to take the radiotherapy unit to the junkyard. Sotelo shrugged it off. “We're still alive,” he told The New York Times. “Maybe the doctors exaggerated the danger.”