A wildfire that spread from forested land into an industrial zone in the municipality of Oraiokastro, near Greece's northern port city of Thessaloniki, blanketed a large area in toxic smoke, local media reported Sunday.

The fire, which broke out Saturday afternoon, swept into the industrial zone and damaged multiple businesses and homes, public broadcaster ERT reported.

An oil processing factory and a recycling plant were still burning despite the efforts of firefighting teams.

Authorities urged residents to keep windows closed and remain indoors as much as possible to avoid exposure to the toxic smoke.

In a related development, five firefighters were hospitalized — three with respiratory problems, one with a hand injury and one due to exhaustion.