Energoatom, a Ukrainian regulatory agency that operates nuclear power plants in the country, warned on Monday that forest fires near Russian-held Chernobyl have raised radiation concerns.

In a March 21 statement, the Ukrainian parliament said that at least seven different fires were spotted near the plant by satellite images of the European Space Agency’s (ESA) Sentinel-2 satellite.

Though the now-defunct plant no longer produces nuclear power, the radiation at the site is consistently monitored, especially after a catastrophe in 1986—when an explosion at the plant became one of the world’s worst nuclear accidents.