Dublin Fire Brigade said eight units were tackling the blaze, which appears to have broken out at St Margarets metal plant.
Residents living near the north Dublin site have been told to avoid the area and close their windows.
A fire spokesman said the fire is “near Dublin Airport” but flights have not been impacted.
Shocking footage and photos from the scene show huge black clouds of billowing smoke filling the sky.
Several cars at a scrapyard are ablaze with a central building also in flames.
Other photos show parts of the site coated in a thick layer of foam.
Warnings have now been issued to nearby residents.
A fire brigade spokesman said: “Firefighting operations are continuing at the vehicle recycling centre in St Margarets. Our aerial drone unit is now on scene to help direct firefighting resources.
“Residents downwind or close to the St Margarets fire should close their windows to prevent smoke entering your home. Avoid the area, especially those with any breathing issues.”
Dublin Airport shared a photo taken across the tarmac of the smoke but said flights were not currently impacted by the blaze.
They tweeted: “There is a fire in St Margaret’s near the airport. The fire is not on the airport campus and the smoke is not having an impact on airport operations.”
A press conference with fire officials will begin shortly.
This is a breaking story, more to follow…