As Ukraine marks 30 years since the worst nuclear disaster in history, you may be confused to see the name of the explosion site spelled two different ways.

Some readers may be accustomed used to seeing the Russian spelling, Chernobyl. However, The Canadian Press wire agency, which many media outlets subscribe to, has transitioned to using the Ukrainian spelling, Chornobyl.

When Ukraine became independent from the former Soviet Union, the Ukrainian government requested that international agencies re-establish the original spellings of Ukrainian cities, regions and names.

The Canadian Press made the switch to Ukrainian spellings in the 1990s, but not every news agency followed suit. The Associated Press and Reuters, for example, still use the Russian spelling of Chernobyl.

For the same reason, readers may note the name of the Ukrainian capital spelled as Kyiv, or Kiev, which is the Russian spelling.