"We're seeing problems with the covering on between six or seven percent of the medals and it seems to be to do with the difference in temperatures," Rio Games communications officer Mario Andrada told reporters Friday (via AFP).
Andrada didn't go into exact details about what exactly he thought was happening, but he called it "completely normal."
Olympic gold medals, for example, are actually just 1.34 percent gold. The rest is made of sterling silver, ABC News reports. And about 30 percent of the silver in those thousands of medals awarded in Rio came from recycled silver.
Temperature issues, however, aren't the only reason some athletes are seeing defects in their medals, according to Andrada. He said some of the defects can be blamed on the athletes.
"The most common issue is that they were dropped or mishandled and the varnish has come off and they've rusted or gone black in the spot where they were damaged," Andrada told Reuters, adding that silver medalists have seen the most problems.
Andrada said he first started hearing of issues with the medals in October, and that Rio organizers and the International Olympic Committee are now setting up a system to get the defective medals replaced by the Brazilian mint that made them.
The heptathlete, who took home a silver in the event in Rio, noted her 2012 gold medal came with instructions to "avoid any sort of impact or abrasion [on the medal]" and "always try to carry it in its box."
Those instructions also said to "only clean it using a soft, dry cloth . . . do not use any liquids, chemicals or abrasive substances when cleaning it." They did not appear to instruct medalists about storing it at a certain temperature.
Medals for each Olympic Games are slightly different, however, so what may affect one given out in 2016 may not affect another given out in 2012.
The medals for the 2020 Games will be even more unique, with the promise of being the most environmentally friendly of all time. Per The Post's Cindy Boren, the medals are slated to be composed of recycled cellphones and small appliances donated by Japanese citizens.
(This story has not been edited by NDTV staff and is auto-generated from a syndicated feed.)