ASTORIA, N.Y. The electrical accident that illuminated the New York City skyline late Thursday night came from a substation next to one of the states dirtiest plants, casting new light on the citys dependence on antiquated oil-burning power stations and bolstering calls for cleaner electricity.

This densely populated area of northwestern Queens provides nearly half the citys electricity from aging plants that burn No. 6 fuel oil, a thick, viscous oil blend considered one of the most polluting energy sources in the world.

The Astoria Generating Station, right next to where the sudden release of heat and light caused a stunning electrical arc flash around 9 p.m., burns 3,039,000 gallons of No. 6 fuel oil a year. The Ravenswood Generating Station, the towering four-smokestack facility on the East River in Long Island City, burns another 3,264,000 gallons per year and was ranked as the states largest carbon polluter in 2014.